Should I go for the Traxler Counterattack? Many of my games as Black feature the Two Knights' Defence.

[FEN ""]
1.  e4   e5
2. Nf3  Nc6
3. Bc4  Nf6

Sometimes my opponent will play 4. Ng5, and I usually reply with 4 ... d5.  It is not uncommon for the play to continue 5. exd5 Nxd5 (because neither of us knows any better - I'm still learning to smell fried liver), and if my opponent is particularly bloodthirsty, 6. Bxd5 Qxg5.

But I've just heard of the Traxler Counterattack, in which I would play 4 ... Bc5!?.  How is that a seriously played course?  With 4... Bc5!? 5. Bxf7+ White wins a Pawn without any compensation for Black that I can see.

The merit that I see in it for Black is when White plays 5. Nxf7.  Even that seems unsteady for Black.

My options as I see it are 1) go for the Traxler (and maybe lose a pawn?), 2) lose a pawn (after 4. Ng5 d5 5. exd5), 3) face a possible fried liver attack (after 5... Nxd5), and 4) avoid  1. e4    e5
    2. Nf3  Nc6
    3. Bc4  Nf6 altogether, perhaps by playing 3... h6 as I've seen some do.  Then again, the "lost" Pawn I've mentioned might be able to be avenged, but how?

The Traxler can be a lot of fun to play if white plays 5.Nxf7?!.  If white plays 5.Bxf7+! instead, then it's a lot less fun.

Before I go any further, let me recommend the following: instead of the Traxler, play 4...d5 5.exd5 and now either 5...Na5 (Morphy variation) or 5...b5 (Ulvestad variation).  Both of these lines feature black sacrificing a pawn in exchange for quick development.

Now, back to the Traxler:

First, the "fun" line, 5.Nxf7?!.  Black should play 5...Bxf2.  Now white can choose between Kxf2 and Kf1.  Both of these lines give black good attacking chances, although black will frequently be down two pieces.  You can take a look at an article from chesscafe for some more information.  Those lines are not really up to date, but it's a good introduction.  If you're interested in these specific lines, that's probably worth a separate question for each since the variations get out of hand very quickly.

The more sobering line, 5.Bxf7+ can really put a damper on black's plans.  The best line now is 5...Ke7 6.Bb3! Rf8.  Now white scores an impressive 69.3% with 7.d3.

Granted most of those games were not top level games, but black's difficulties are apparent.  White has not committed to castling kingside yet, and can start trades with a plan like Nc3-d5.

So to wrap up, if you want to play the Two Knights defense (3...Nf6), you have to be ready for 4.Ng5, and you should take a look at the Morphy variation and the Ulvestad.  Both of these lines give black good chances for a win, even though black sacrifices a pawn.  Playing a quiet move like 3...h6 or 3...Be7 is not really good, although both moves stop 4.Ng5.  The problem is that neither h6 nor Be7 really help black develop around the center, and white can react immediately with 4.d4!.

At the top level, black will usually play into an Italian game with 3...Bc5 instead of the Two Knights.  The only real gambit in this case is the Evan's Gambit with 4.b4.  Again, all of these variations probably deserve their own question, but hopefully this is enough to get you started.


Guide to understanding engine analysis output Not having played for decades, I am getting back into chess, with all the great programs. I have Shredder 13 and Fritz 17. Both can output very impressive analysis. But for an effective newbie, where can one find out how to understand and interpret this detailed information? The manuals are totally missing any useful help. Apologies for such a newbie question, but the point is I would like to understand how I can improve my game by through the engine generated analyses. All I understand presently is the figure that represents the advantage estimate. There are tens of thousands of videos on chess. So far I have not found one dedicated to this topic.

I'm not sure what you're asking.
Chess analysis programs go through all possible moves for some number of (half-)moves starting from a given board position. They evaluate the static board position at the 'depth' to which they're set to analyze, and return a score for the position. This is not how any human plays the game, of course.
When the engine recommends a move, it is indicating that that move got the highest score among other moves possible from that position. Its static board evaluator might know about control of the center, or control of more space, or having two bishops, but it knows about them in terms of evaluating a single board position and scoring it, not in terms of deciding that that principle applies in a given situation and making moves on that basis. It's a subtle difference, I guess, but very real to the programmers.
Other than that, you get negative scores for Black advantage, positive for White, the numbers increase for more advantage.
In the end, about all you can do with the output of chess analysis is see the moves they regard as 'best' (and maybe 2nd and 3rd best) from any position and try to figure out how you would have known to make those moves and not some other moves. You can try other moves and figure out what would have happened, why they are worse.
If you have another question, can you make it more specific?


Can one mate a lone king with Bishop and two knights without being aided by the attacking king? In order not to overload the answer to this question, I split off the bishop+two knights part. So the question is: Is it possible to mate with a bishop and two knights without the help of the king?

Work in progress

You can convince yourself easily, that mate is only possible in a corner of the board. We distinguish four cases:

The corner is the same color as the bishop and the bishop mates
The corner is the same color as the bishop and a knight mates
The corner is the opposite color as the bishop and the bishop mates
The corner is the opposite color as the bishop and a knight mates

For the following analysis we only consider unique positions that are not related by symmetry. Also we don't distinguish between similar positions of a bishop along a diagonal, if the same essential square(s) is covered.

Starting with the first case, bishop same color as the corner and the bishop mates. There are 5 distinct (up to symmetry) mating positions: 1.1a to 1.1e.

Doing a retro-analysis for 1.1a and 1.1b:

White's last move was Bb7+ and the bishop came from c8 or a6.
Black's last move was Ka8 and the king came from b8 or a7. The king was not forced to go to the corner and could have escaped to c7 or b6 instead.

Doing a retro-analysis for 1.1c, 1.1d and 1.1e:

White's last move was Be4+ and the bishop came from somewhere along the b1-h7 diagonal.
Black's last move was Ka8. If the king came from b8 or a7, it could have gone to b7 instead of the corner. If the king came from b7, it could have gone to (among others) c6 instead of the corner.

So in conclusion, it is not possible to force a mate with the bishop in the corner of the bishop's color.

The second case, bishop same color as the corner and the knight mates. There are 2 distinct (up to symmetry) mating positions: 1.2a and 1.2b.

White's last move was Nb6+ and the knight came from a4, c4, d5, d7 or c8.
Black's last move was Ka8. If the king came from b7, it could have captured Kxc6 instead (note that the c6 knight was not protected then).

If the king came from a7 or b8, there is actually a longer series of forced moves leading to mate! Needs further invetstigation.

2. Corner opposite to the bishop's color

2.1 Bishop mates

You easily see that there is not even a theoretical mating position for this case.

2.2 Knight mates

You easily see that there is not even a theoretical mating position for this case. In order to mate, one knight would have to check the king in the corner, say a8, the other knight would have to cover the light square b7 and the bishop would have to cover both a7 and b8 which it cannot.


How many positions per second can a modern supercomputer calculate? If we created a very powerful supercomputer (as powerful as the current most powerful supercomputers) which was only designed to find forced mates, how many positions could it calculate per second?

I only need an approximation. And remember, the computer doesn't waste time evaluating every single positions (like normal engines do); it just calculates as far as he can until he finds a forced mate (if there is any).

I tried to find the answer to the question myself, but I'm not sure at all if my conclusion is correct. So what follows may be wrong.

I found that the supercomputer Deep Blue "was capable of evaluating 200 million positions per second" (from Wikipedia).
But Deep Blue was old, supercomputers have became much more powerful since 1997, and Deep Blue wasted time evaluating every positions.
Therefore 200 million is only a lower bound for the answer to this question.

Since Deep Blue had a performance of 11.38 GFLOPS, and the current most powerful supercomputer (Tianhe-2) has a performance of 33.86 PFLOPS = 33 860 000 GFLOPS, we could estimate that the answer would be closer to 200 000 000 * 33 900 000 / 11.38 = 6 * 10^14 = 600 trillion positions per second. That seems like a lot, but taking into account that in average a position has around 35 legal moves, given 3 minutes such a computer would only be able to calculate every single positions up to a depth of 11 plies. Since Deep Blue wasted time evaluating every single of those 200 million positions per second, I believe Deep Blue should have been able to calculate approximately a billion positions per second if it didn't have to evaluate them.

So the true answer to the question is probably closer to 3 * 10^15 = 3 quadrillion positions per second. That's still not much: given 30 seconds it would just be able to calculate everything up to a depth of 11 plies. Even given an entire year it would only be able to calculate every positions up to a depth of 15 plies.

To answer the question in the title: In chess programming, perft is used for debugging move generators and testing their performance: the goal is simply to calculate the number of possible ways the game could continue until a mate or a stalemate for the next N moves. Modern engines give around 10-100 million nodes per second using one core of a modern processor. This program apparently searches 20 billion nodes per second using a modern GPU instead of a CPU.

However, as I said in the comments, searching for a mate in N moves is very different than searching all possible moves until that depth. The following observation is the heart of alpha-beta pruning: for example, if you have found that after 6.Nc3 Qxb4 7.Nd3 white can mate, there's no need to see what happens after 6.Nc3 Qxb4 7.a4.
Another, perhaps more likely example: You have found that the position after 5.e3 is drawn, and then find out that 5.e4 Qc7 gives a draw, too. Now we already know that the position before 5.e4 is at least a draw for white, and find out that the position after 5.e4 cannot be a win for white. Because it does not matter whether white draws or loses after 5.e4, we don't have to see what happens after 5.e4 Qb6.
As you probably can see, move ordering is critical here: it is beneficial to search best moves first. In fact, with perfect move-ordering, alpha-beta can reduce the number of searched nodes to approximately square root of the original value. So with perfect move-ordering, the number of positions needed to search for mate in 10 plies would be 35^5, not 35^10. But to get a good move ordering, one needs to do something else than just generate moves: perhaps evaluate the intermediate positions to get a good hint of the values of the moves. Of course, for the search of mate in, say, 20 plies, the best evaluator function would probably be different than what is used in engines designed to play a full game of chess.


How to win a rook endgame with two extra pawns-4 vs 2 general plan In this diagram it's White to move. Black should be winning in this endgame. I want a simple plan on how to move the Black pawns in a way that I will avoid the horizontal and vertical checks from the White rook.
[fen "8/R4ppp/4pk2/1r6/8/5K2/6PP/8 w - - 8 40"]

Sometimes I get stuck in a blitz game because I don't have a plan how to win such kind of positions. I would really appreciate it if somebody can give me a straightforward plan. My plan was to keep the Black rook on the 5th or 4th rank to cutoff the White king and advance the h and g pawns. But then what?!

My plan was to keep the Black rook on the 5th or 4th rank to cutoff
the White king and advance the h and g pawns. But then what?

Your plan is a bad one.
The general rule in rook and pawn endgames is:

Your king protects your pawns
Your rook attacks your opponent's pawns

You can add another one:

Push your passed pawns

As you can see your passed pawns are not your g and h pawns. Therefore you should not be pushing those pawns as a first priority. You may want to push them to help the e and f pawns to advance.
Regarding "Cutting-off the opponent's king", in rook and pawn endgames it is usually much more important to cut off the opponent's king vertically not horizontally. You want to cut off the king from where the pawn or pawns are going to be. The White king on the 3rd rank is not cut off. If you are going to make a queen then sooner or later one of your pawns is going to have to try and reach the 3rd rank when the White king would be ideally placed. The white king on the a or b file would be cut off.
Your king is already protecting your pawns but your rook is not attacking your opponent's pawns. In the changed position with White's king now protecting the g pawn the best way to attack the pawns is not the immediate Rb2 because there is a more efficient way to do that.
First Rb3+ either forces the king to the fourth rank or to the second rank. In either case the move Rb2 then comes with tempo. The White king has to move.
Then you want to try and push f6 or f5 to get your e and f pawns rolling. Your king will need to be out of the way on g6 and you will want to move the h and g pawns up so they aren't vulnerable to attack by the rook. So g5 creates space on g6 for your king. You can follow up with h5 and then get ready to push the f and e pawns. Your opponent can try and stop this by g4 or just sit and wait passively.
One line might be:
[fen "8/R4ppp/4pk2/1r6/8/5K2/6PP/8 b - - 4 38"]

1... Rb3+ 2. Kg4 Rb2 3. Kf3 g5 4. h3 h5 5. g4 (5. Rc7 g4 6. hxg4 hxg4 7. Kxg4 Rxg2) Rb3+ 6. Kg2 h4 7. Ra6 Rg3+ 8. Kh2 Kg6 9. Rb6 Re3 10. Ra6 f6 11. Rb6 e5 12. Ra6 Rf3 13. Kg2 Rd3 14. Rb6 Kf7 15. Ra6 Ke7 16. Rb6 Rd6 17. Rb2 Ke6 18. Rf2 (18. Re2 Rd4 19. Rf2 e4 20. Rf5 Rd2 21. Kg1 Rd3 22. Kg2 Rg3+ 23. Kh2 e3 24. Rf1 e2 25. Re1 Re3)  e4 19. Re2 Ke5


Amazon vs Chancellor endgame Many online sources (such as Wikipedia) state that the endgame of amazon (piece that moves like Queen and knight) and chancellor (piece that moves like rook and knight) is a draw. I did some experimenting but could not find such a position. Now Wikipedia says that a draw can be forced with a fortress that forces the stronger side to give perpetual check without giving such a position.

Examples of positions I've tried are (the queen represents amazon and the rook represents chancellor):

[Title "Centralized king"]
[FEN "8/8/8/3kr3/8/8/8/KQ6 w - - 0 1"]

1. Qb4+ Ke6 2. Qf4 {Forces the chancellor into a pin} Kd6 3. Kb2 {Waiting move, and now the king must leave the chancellor} 1-0

or

[Title "Cornered king"]
[FEN "kr6/8/8/8/8/8/8/KQ6 w - - 0 1"]

1. Qe4+ Ka7 (1... Rb7 2. Qe8+ Ka7 3. Qc6+ Ka8 4. Qc8+ Rb8 5. Qc7#) 2. Qc5+ Rb6 (2... Ka8 3. Qc7#) 3. Ka2 {Any king move is followed by Qxb6#} 1-0

or

[Title "King on rim"]
[FEN "4k3/4r3/8/8/8/8/8/KQ6 w - - 0 1"]

1. Qb8+ Kf7 2. Qd6+ Kf8 3. Kb2 Kg8 4. Qxe7+ Kh8 5. Qf6#

All three of these examples lead to trivial wins for White. Could someone post a fortress in this endgame, if such a fortress exists at all?

This is a great question and a fun problem to mull over. Indeed the way it's written on wikipedia one gets the impression that amazon-vs-empress fortresses are trivial and easily attainable for the weaker side, where in fact it's very difficult to even come up with dummy examples where the empress stands any chance of holding (so not surprising not to see a example diagram there). In other word, most amazon vs empress (also known as chancellor) endgames are in fact winning for the side with the amazon (intuitively, the amazon has diagonal routes towards the weak points in the empress' safezone), not even requiring the assistance of the king in order to dominate the empress+king duo.

Some intuition: You want to have the king of the side with the amazon to be well cornered by both the empress and the king, or at least for it to be in a different quadrant of the board compared to the amazon and near the opponent king (so all cases where the amazon and the king are somewhat central is highly likely to be winning already). The reason for this setup is that it allows you to defend certain checks with an empress-fork thus forcing the draw, while covering some key squares with the empress that otherwise would be exploited by the amazon to push the king towards the center and reach a winning situation again. One of the better scenarios for the amazon side would be: to pin the empress while having spare waiting moves with their king.

Note that in the diagram editor here the rook and queen will denote the empress and amazon respectively. Additionally, certain moves that would be illegal in standard chess thus disallowed by the diagram editor here, as we're using rook and queen instead of fairy pieces, would be mentioned in the annotations.

It's funny, if you just try to randomly set up any amazon vs empress ending, they're almost always losing for the empress-side. Now even though it is still possible to find some clear setups where the empress holds, it's important to note that fortresses of this kind constitute a minute fraction of the state-space of all legal amazon vs empress endgames. This observation is well corroborated by the statistics provided here for KA vs KC (C for Chancellor/empress): If you look at the third row in that table with the percentage breakdown, only 0.001052 % of all legal KA vs KC configurations comprise fortresses, with most other draws being by perpetual. The latter types of examples are simpler to showcase specially if it's the empress' side to move, whereas fortresses with the amazon side to move are highly non-trivial. Below some examples for both types of draws are showcased (annotated):

Fortress and perpetual examples:

 [title "empress+king fortress example#1 - black to move"]
 [fen "k7/8/K7/6q1/R7/8/8/8 b - - 0 1"]
 [StartFlipped "0"]

 1...Kb8 {the only amazon moves either force the draw immediately or lose on the spot because of the Rb6# threat. So only attempt is to move the king and try to escape but 2.Rb6+ Kc7 3.Rb5+ forces the draw with a fork. Thus, white is holding here.}

Another example:

 [title "empress+king fortress example #2 - black to move"]
 [fen "k7/6q1/K7/1R6/8/8/8/8 b - - 0 1"]
 [StartFlipped "0"]

 1...Qa1+ {Again all key squares c7-b7-a7 are well covered, and any check on the 6th row loses immediately, so black's only other attempt is Qa1+} 2.Ra5 Qf6+ (2...Qf1+ 3.Kb6+ Kb8 {and black even gets mated here: 4.Rc6+ Ka8 5.Rc8#}) 3.Kb5+ Kb8 {and 4.Rc6+ forking and forcing the draw}

Now to show you how sensitive these fortresses are, let's take example#2 again with the added difference that the amazon is now in a position to pin the empress on the f1-a6 diagonal, and that suffices to break the fortress and win:

 [title "Losing variation of example#2: Amazon pins can be deadly!"]
 [fen "k7/8/K7/1R6/8/8/7q/8 b - - 0 1"]
 [StartFlipped "0"]

 1...Qe2 {pinning and the Zugzwang's set: both remaining king moves are losing} 2.Ka5 (2.Kb6 Qc4+ 3.Ka6 Qa4+ 4.Ra5 Qb4#) Qc4+ 3.Ka6 Qa4+ 4.Ra5 Qb4# (1...Qa2+ 2.Ra5 {setting up a discovery on the king while covering c4} Qe6+ (2...Qe2+ 3.Kb6+ Kb8 {4.Rc6+ Kb8 5. Rc8# mate.}) 3.Kb5+ Kb8 {and the 4.Rc6+ fork forces the draw.})

Finally, here's one trivial perpetual example:

 [title "Example#3 - perpertual, empress-side to move:"]
 [fen "7q/8/6k1/8/4K3/5R2/8/8 w - - 0 1"]

 1.Rf4+ Kg7 (1...Kg5 {leads to similar perpetuals}) 2.Rf5+ Kg6 {black can avoid the repetition but only at the cost of trading the remaining pieces.} (2...Kg8 {is followed by 3.Re7+ Kf8 4.Rc8+ winning the amazon}) 3.Rf4+

Other variations that look tempting:

Here's one that resembles a fortress but it probably isn't. The ideal scenario for the empress side would be something like 1...Qf8 after which the empress would try to check the king endlessly as it cannot hide behind the amazon anymore. But white doesn't have to play 1...Qf8, instead, staying on the long diagonal with a waiting move probably wins, e.g., 1...Qf6.

 [title "Example#4: other attempts worth considering"]
 [fen "8/8/8/5q2/8/2k5/1R6/K7 b - - 0 1"]
 [StartFlipped "0"]

 1...Qf8 {Any amazon check results in a fork forcing a draw, so we have to either make king moves or waiting amazon moves.} (1...Qf6 2.Kb1 {any rook move also loses on the spot, e.g. 2.Rb1+ Kc2+ 3.Ka2 Qe6+ 4.Ka1 Qa6+} Qf1+ 3.Ka2 Qc1+ 4.Ka3 Qxb2#)

Notice that any such pin with the king stuck in the corner is always losing, for instance:

 [title "Example#5: Pin exploitation to dominate the empress"]
 [fen "8/8/8/3k4/3q4/8/1R6/K7 b - - 0 1"]
 [StartFlipped "0"]

 1...Qg1+ 2.Ka2 (2.Rb1 Qa7+ 3.Kb2 Qa4+ 4.Kc1 Qa2+ {winning the empress}) Qc1+ 3.Ka3 Qa1+ 4.Ra2 Qb1+ {winning the empress}


What are some chess songs? What are some songs about chess?

Historical songs; pop songs; singalong songs, hymns, anthems; whatever you can find.

One Night in Bangkok- Murray Head
http://www.youtube.com/watch?v=R9cNtrrCP0E&feature=kp

A cover of Adele's "Skyfall" with a chess-themed music video
https://www.youtube.com/watch?v=oiXJQ0SG888


Outside-the-box mate-in-one challenge I've received an (I would say impossible) mate-in-one challenge and I have already checked all movements, but couldn't solve it yet. It came from a trustable source and they say you need to think outside the box, so certainly there's a solution. Can someone help me to find it out?

 [FEN "2q1rb2/pR3pkr/3p2pN/2nPp1QP/1nB1P1b1/6N1/PBP3P1/5RK1 w - - 0 1"]

1. Qg6 Kh8 (1. Qf6 Kh6) (1. Qe5 Re5) (1. Be5 Re5) (1. Ngf5 Kh8) (1. Rff7 Kh8) 2. Qg8

White moves, and it is pretty close to win. Qxg6, Qg8 could be a two-movement winning sequence. However, as said in the challenge statement, it is possible to be victorious in the very next movement, so I have been wondering how!

The original statement is:

  Today's puzzle is one of the most trickiest chess problems you'll ever see. All you need is to think outside the box. White to move and mate in one! Yes, in one move. No, no extra pieces are appearing on the board likewise no removal. It's achieved with one unique valid movement, are you able to solve it?

There's just 6 possible checks white can do (I mean, i just saw 6). All them are included in above board followed by how black escape from it.

Can anyone find the solution?

Also also also also, for honesty here, I googled the FEN to find the answer.

I checked with Stockfish and indeed there is no normal mate in one for White, and there isn't a mate in one for Black either. So this obviously a trick/joke problem.

The trick is this: What last move of Black would allow a mate in one?

Solution:

   The mate in one is “1. dxe6#” en passant! This move takes away the Black king's only flight square on h8, which is what stops any other attempts by White.

Explanation:

   The joke is that it can't be proved that Black's last move was “0... e5”. The accepted convention in chess problems is that an en passant capture is only allowed on the first move of the solution if it can be proved that the captured Black pawn made the double-step as Black's last move. It is obvious that Black has plenty of possible last moves other then e5, hence why this a trick problem.


Why don't chess tournament organisers use top-down camera angles? I don't watch chess tournaments because it is such a poor experience. The live stream of the players showcases the board at an angle and I struggle to see what is going on.

Meanwhile, the digital image of the board that is usually also there is often behind the actual game. In classic, maybe not a big deal, but it's a dealbreaker for blitz and rapid.

Why don't chess tournaments solve this issue by using a top-down camera angle? It's not hard to extend the camera down from a pole attached to the roof, or you can even use a camera connected to a flexible cable which you can extend and then curve downwards, kind of like on a lamp:

This would then give the following much more clear viewing experience:

Obviously you'd use a high quality camera, and you also need to use pieces which are more easily distinguishable from a top-down view, which are both minor changes, that could lead to great improvement.

I see a couple of reasons not to do this:

It's a lot harder to distinguish the pieces. For example, bishops and pawns look really similar, and the black queen and king look similar too.

When you watch a game as an on-site spectator, you don't view it top-down either. Even better: the players themselves don't view the board top-down, but from an angle.

Video streams are often accompanied by a live analysis board, which is top-down and offers much more (the remaining time for both players, the evaluation of the current position and the best lines according to a strong engine). A top-down video stream would basically duplicate this.
They can, as you say, be a little out-of-sync with the video (on a slow connection, the live board can be even faster because of buffering) but that seems (to me) like a better problem to tackle. Maybe the next generation of livestreams will be able to do this?

The lamp standard in your picture would rather annoy me as a player, but hanging from the ceiling (like some other lamps) would bypass that particular problem.


Why does white not play cxd4 here? I am Black and my opponent is White. Here the computer recommends Rxd4, which I have done (the rook captured bishop here).
[FEN "4r1k1/1pp2pp1/p6p/4q3/P2rPn2/2P1QP1P/1P4P1/R4RK1 w - - 0 1"]

It's obvious then that Qxd4 is a blunder, because then I play Ne2 to fork the king and queen and the game is over. I would expect the computer to play cxd4 here to go up material, but the computer plays Rfe1.
Why not cxd4 here? What future sequence am I not seeing?

Stockfish, at depth 20, evaluates Rfe1 with a score of -8.5, while cxd4 has one of -2.6. With so large a difference, the explanation is that
you were playing against a weak computer. There is usually
a gradient (e.g. from 1 to 10) of difficulty to choose from
when playing against a computer, so you have probably chosen something
far from 10. Chess.com (guessing from the screenshot) also has
adaptative opponents that will grow stronger/weaker according to your
performance.
For what it's worth, shortly after cxd4 White gives up a rook and a pawn
for Black's knight and has an exposed king and piteous pawn structure —so Black wins anyway—, as follows.
4r1k1/1pp2pp1/p6p/4q3/P2rPn2/2P1QP1P/1P4P1/R4RK1 w - - 0 6

1. cxd4 Qg5 2. Kf2 Qxg2+ 3. Ke1 Qxb2 {Double threat: Qxa1+ and Ng2+ (a royal fork)} 4. Qxf4 Qxa1+ 5. Ke2 Qxd4


Why is the Exchange French considered drawish? Why is the Exchange French considered so drawish since it is very early in the game, so it seems like there would be a lot more play left. A lot of lower rated players play it against me, although I am not that strong myself.

Well, first, when you are lower-rated, there really is no opening that can be considered drawish since it takes a fair amount of skill to be able to draw at will. That is often a skill associated more with the Grandmaster ranks, and maybe some solid IMs too.

Assuming that someone has the skill to draw, it really comes down to the ability to exchange pieces to get to an even endgame, mostly the rooks on the e-file, but also the Bc1 might go to f4, when black will want to trade off the well-placed piece rather than keep the B on e7, where it inhibits the rook trades I just mentioned. This trade is advantageous to white since although his B is not super bad, it is still technically a bad B for good B exchange that might be most troublesome for black if they get to certain endgames later.

Another thing that is interesting is that the Exchange French has a quite a number of players, who have overwhelming scores with it. None other than Kasparov played it three times in tournament games against Bareev, Short, and Kortchnoi. He scored 2.5/3. Other undefeated GMs include: GM Najat Abassov was 4/5, Michael Adams 4.5/5,  GM Dmitry Andreikin 6.5/9 (and there are plenty more, but it would have been a project to keep going). GM Etienne Bacrot had one loss, but has a record of 13 wins, 1 loss, and 3 draws with it as white. I think that this is because there can be significant danger if your opponent assumes that you are trying to draw, when you are really trying to win.

I played 1.e4 until I was 1935 USCF, and I played a line of the Exchange French with an early Qf3 that I found Kortchnoi had played with success. My OTB record with that was 6 wins, 1 loss (In the very first game with this as a 1700, in a winning position, I let my queen get trapped…oops).

Granted, my opponents were weaker then, but what I found was that black never paid enough attention to the e-file, which was their downfall. The other point is comfort: Many French players do not like this type of position, while white must be reasonably happy since he is playing it. Having “your kind of position” is a major part of winning chess. I would double the pawns on f6, and take the file, and just win; or trade a N for a B on e6, and what was left was bad. Here are examples of each.

[title "Kevin Cotreau 1735 - Terry Messa 1830, Cole Younger Open, 1984"]
[fen ""]

1. e4 e6 2. d4 d5 3. exd5 exd5 4. Bd3 Nc6 5. c3 Bd6 6. Qf3 Qe7+ 7. Ne2 Nf6 8. Bg5 Be6 9. O-O h6 10. Bxf6 gxf6 11. Ng3 O-O-O 12. Nf5 Bxf5 13. Bxf5+ Kb8 14. Nd2 Qf8 15. Rae1 Qg7 16. Re3 Ne7 17. Bh3 Ng6 18. g3 c6 19. Rfe1 h5 20. Bg2 h4 21. Nf1 hxg3 22. fxg3 Nf8 23. Re8 Ne6 24. Rxd8+ Rxd8 25. Ne3 Ng5 26. Qg4 Re8 27. Kf2 Ne6 28. Qf3 Qg6 29. Nxd5 Rh8 30. Nxf6 Rxh2 31. Nd7+ Kc8 32. Ne5 Bxe5 33. Rxe5 Qc2+ 34. Re2 Qg6 35. Kg1 Rh6 36. Re1 Qf6 37. Qxf6 Rxf6 38. Bh3 Kd7 39. Rf1 Rxf1+ 40. Kxf1 Ke7 41. Bxe6 Kxe6 42. Kf2 Kf5 43. Kf3 a5 44. g4+ Kg5 45. c4 f5 46. gxf5 Kxf5 47. Ke3 b6 48. a4 Kf6 49. Ke4 Ke6 50. d5+ Kd6 51. Kd4 cxd5 52. cxd5 Ke7 53. Ke5 Kd7 54. d6 Ke8 55. Ke6 Kd8 56. d7 1-0

and

[title "Kevin Cotreau 1735 - Gary Field 1940, NH Amateur, 1984"]
[fen ""]

1.e4 e6 2.d4 d5 3.exd5 exd5 4.Bd3 Bd6 5.c3 c6 6.Qf3 Be6 7.Ne2 Qc7 8.Bf4 Ne7 9.O-O Nd7 10.Nd2 Ng6 11.Bxd6 Qxd6 12.Bxg6 hxg6 13.Qg3 Qe7 14.Rfe1 O-O-O 15.Nf4 Qf6 16.Re3 Rde8 17.Rae1 Nf8 18.Nf3 {idea Ng5} 18...Nh7 19.Nxe6 fxe6 20.Qd6 Nf8 21.Ne5 Qf4 22.h3 Rd8 23.Qe7 (23.Qc5! Kb8 24.Rf3 Qd2 25.Rf1+– {The ideas of Rf7 followed by Nc6, or Nf7 are unstoppable.} 25...Nd7 (25...Qxb2 26.Nf7 Nd7 27.Qd6+ Kc8 28.Nxh8 Rxh8 29.Qxe6+–) 26.Qd6+ Kc8 27.Rf7) 23...Qh4 24.Qxh4 (24.Qa3! Kb8 25.Nf7+–) 24...Rxh4 25.Rf3 Re8 26.Rxf8 Rxf8 27.Nxg6 Rff4 28.Nxh4 (28.g3?? Re4) 28...Rxh4 29.Rxe6 Kd7 30.Rg6 c5 31.Rxg7+ Kc6 32.dxc5 a5 33.Rg4 Rh5 34.b4 a4 35.Rd4 Re5 36.Kf1 Re6 37.f4 Re3 38.f5 Rxc3 39.f6 Rc1+ 40.Ke2 Kd7 41.Rxd5+ Ke6 42.Rd2 Kxf6 43.Kd3 Kg5 44.Rc2 Ra1 45.Kc4 Rb1 46.Rc3 {To prevent a2 and Rb2.} 46...Rb2 47.Ra3 Rxg2 48.Rxa4 Kh4 49.b5 Kxh3 50.Ra3+ Kh4 51.c6 Rg4+ 52.Kc5 Rg5+ 53.Kb6 bxc6 54.bxc6 Rg6 55.Kb7 1–0

Ultimately, if you find this to be a real problem, then you might want to just play something else when facing players, who are much lower-rated since most higher-rated players probably will not play it to begin with.


Which openings offer the best chances to reach an endgame quickly? If you are strong at endgames, which openings are favorouble for you
 because they tend to lead quickly to an endgame ?

The Berlin comes to mind.

White can avoid this famous endgame, but only at the cost of relinquishing any prospects for an opening advantage.

Generally I have a hard time coming up with openings leading to endgames. There are rather variations within openings that are endgame prone.

To find variations like the Berlin I advice you to look at the games of Ulf Andersson. He is famous for going into the endgame as quickly as possible.


How good can I get just by playing? On blitz 3|2 I am rated around 1000. I love playing the game and usually I play with players around my level. I try to play against slightly better players. Assuming I am not reading chess books or otherwise get a training besides playing the game, how good should I expect to get?

And an interesting question you pose as to how good you could become playing 3|2.
The 3 min plus 2 second increment you play means roughly say a move rate overall of about say 6 seconds per move for an average game of 50 moves.
You try to always play slightly stronger players, excellent idea, so assuming you are not getting trounced ie at least breaking even I think you will progress perhaps to 1200 to 1300.
Games will be won or lost mostly by one or two move combinations  or simple oversights by you or your opponent.
Not an issue if you are playing mainly for the enjoyment of chess.
But if your real focus is to become a strong player this is a different matter.
To put your question into perspective consider other endeavours.
Would you expect a carpenter who only built small wooden boxes in five minutes to be able to build you a good house?
A computer programmer who only spent six seconds on each line of code to become an excellent programmer without further study or deeper reflection?
If your main goal is to improve you need to start playing longer games and to play through master games that are annotated.
You will notice a more rapid improvement in your games though it will require some dedicated work.
Don't go overboard on opening theory, just aim to get a playable position out of the opening.
But it is in the end-game that playing strength really shows so make some serious effort in this phase of the game and you will improve dramatically.
After studying endings you will find your middle game will start to improve as well because you now are aware of which endings to aim for and which to avoid.
Before the internet era I did not have much chance to play over-the-board so I played correspondence chess. This long style of chess forces you to carefully analyse your moves and to study openings and endgames otherwise you could be stuck with a bad position for a year or two!
When I did get to play OTB I did regularly get behind on the clock but managed to bowl over quite a few strong players including some with titles.


Openings in King of the Hill As you probably know, "King of the hill" (KOTH) is a variant of chess where one can win either like in classical chess or by putting the king in the central squares, namely d4, e4, d5 and e5, by a legal move.

I would like to collect some information about opening in this variant. More precisely, we can try to answer the following questions.

What are some examples of opening which are reasonably good in normal chess but almost losing in KOTH?
Conversely, are there some examples of opening which are reasonably good in KOTH but almost losing in normal chess?

As mentioned already, most hypermodern openings (King's Indian, Modern, etc.) are dubious in KOTH, because they give the opponent too much space in the center.

Besides that there are gambits where the compensation mostly consists of better control of the center, which is of course more valuable in KOTH. Therefore, some of such gambits that are often considered to be slightly inferior to dubious in chess are good or even best moves in KOTH. Usually, the gambit pawn should be rejected in order to get a playable position. A few examples are:

King's gambit
Smith-Morra gambit
Latvian gambit
Blackburne gambit (Scandinavian)
Halloween gambit [a piece gambit]

Furthermore, openings/gambits which try to drive the opponent's king to the center can be close to losing in KOTH. A notable example is the Fried liver attack. After 7.Qf3+ black should play 7..Qf6! followed by Be6 instead of 7..Ke6 in order to threaten the exchange of the white queen and bishop, which gives black a considerable advantage.

In order to double check my evaluation of the above mentioned openings in King of the Hill, I used the multi-variant Stockfish fork that is also used for analysis on lichess.


Does FIDE make any money from media coverage? Unlike any other professional sports I know of, everyone seems to be able to broadcast chess world chess championship online.

That raises the question, are they making any money from media coverage? Can't they sell exclusive coverage to selected media?

FIDE have sold the rights for the current world championship cycle to Agon. Given the very high levels of dissatisfaction with Agon it is unlikely that the contract will be renewed and the rights will revert to FIDE. There has been discussion of this on chess.com here.

Note that the moves of the game cannot be legally protected via copyright laws etc. Only the live pictures of the players playing the games can be protected like that. This has already been tested in the courts in several countries including the US (the most lucrative market) by Agon for previous matches.


Tarrasch defense with 6. dxc5 Chesstempo database gives white over 65% in all the variations after 6. dxc5 (130 games with both players 2200+). It has been used by Anand and Ivanchuk. So why the main line 6. g3 is way (2800+ games with both players 2200+) more popular where black scores much better?

It has to be because of black's preparation. But what should be the correct response? I don't see one using the database. Nor can I find one using chess engine.

[Event "?"]
[FEN ""]

1. d4 d5 2. c4 e6 3. Nc3 c5 4. cxd5 exd5 5. Nf3 Nc6 6. dxc5 d4 7. Na4 Bxc5
( 7... b5 8. cxb6 axb6 9. e3  )
( 7... Bf5 8. e3 d3 9. Qb3 )
8. Nxc5 Qa5+ 9. Bd2 Qxc5 10. Rc1

6. dxc5 is just a good move, and you cannot really hope to refute it. It was given an exclamation mark in Grandmaster Reportoire 10 by Ntirlis and Aagard, and their main line starts as in your diagram.

Moves such as dxc5 were underestimated by older theory because they were thought to give the initiative to black. Nowadays with computers we can analyse more concretely and see if blacks initiative is something to be afraid of or not. In the case of 6. dxc5, the analysis seems to suggest that white ends up with a small advantage.


What is the most sound, yet still sharp, gambit? I have played chess seriously for a little over a year and my style is an aggressive one. I started off playing really dubious gambits (at least in my opinion) like the King's Gambit and the Latvian Gambit, immediately looking to give away material for active play right from the opening. I have since toned down my aggressiveness, preferring much more quiet openings like the Ruy Lopez and the Pirc. I really want to re-ignite my gambit play and I need some suggestions on sound gambits I could go for and why.

The Evans Gambit is probably one of the most sound. It's still occasionally played at GM level and most of the critical lines are rarely if ever tested.
The Vienna Gambit and Blackmar–Diemer are probably playable. The Scotch gambit is playable although I wouldn't be surprised if there isn't a forced draw.
With black the Benko is probably sound and the Budapest is playable. Black has fewer sound gambit options since black starts out a half tempo down. Giving up a pawn for a move just gives you an equal position but you're down a pawn.
I'll add though that virtually any opening is playable below 2000 level and certainly in rapid or blitz. In fact, you could probably get to around 2300 with any normal openings.


Where can I find a good chess database? What is the best chess database out there (quality vs. price). Do you recommend online or offline chess database. Any experience with chessbase, chessok, chesstempo or openingmaster?

The TWIC (This Week In Chess) database is your best bet. It's free, has millions of games (many of which are recent and up to date), and is of a high quality.

Here's the link:
http://theweekinchess.com/twic

When you get there, scroll down to the "TWIC Downloads" table and download all the PGN or all the CBV files.

After downloading everything, merge all the games into one database in ChessBase.

Then, you can make this database your reference database (if you don't know how to do this, look up a YouTube tutorial on ChessBase's official channel).


Where can I find a free list of a strong GM (2575+) annotated games? Where can I find a free list of strong GM (2575+) annotated games?

www.chessgames.com has a big collection of annotated games.


Story of unexpectedly high (400+) Elo rising in few months (reaching 2500 Elo mark) I'm sorry for being vague, but that's exactly my problem: I can't find an online blog post of a German/Scandinavian master anymore which illustrated a case of a young boy from Eastern Europe who managed to reach 2500 mark (in a few months time span) thanks to some suspect tournaments and timing.
His coach fine-tuned everything to exploit the delay in updating the Elo list, combined with an excellent performance on a local tournament.

Does anyone can recall a similar story?

I'd really love to read the post again. It was backed up with data from the FIDE official site.

Ok, I finally got it!!!
Here is the link I've been looking for:
Zibbit's blog


What is the importance of pawns in the endgame? How important is it to have more pawns in the endgame phase? Does the power of the individual pawns decrease or increase as the game progresses and why?

Having more pawns than one's opponent (assuming non-pawn material is even) is extremely important in the endgame. Many games of chess boil down to endings where one side has just a single pawn more than the other, and all the action centers around the attempt to promote. In fact, one could not unreasonably define endgames, as opposed to middlegames, as those positions in which the main direct objective is to queen a pawn. (There are plenty of alternative definitions as well, none of which can be perfect.)

A one-pawn advantage is certainly not always enough to win, but the mere fact that having one extra pawn is very often a winning advantage shows just how important the pawn count is in the endgame, and in this sense I would say pawn "power" (to use your wording) does increase as the game goes on. It is a pretty reliable rule of thumb that the side with the material advantage should look to trade pieces and avoid trading pawns; conversely, the defender usually strives to trade off as many pawns as possible in order to increase the chances of a draw. Again, this is just a rule of thumb, and one of the beauties of chess is that one constantly encounters exceptions to such "rules," but this advice will generally steer you in the right direction.


How do I check if a move is legal using Stockfish? Let us say that I input a wrong move in Stockfish. What answer will Stockfish send me back? Or is there a function to check if a move is bad?

People, I found a solution by myself.

Stockfish assumes that all FEN positions you feed it are legal positions. If you feed it an illegal position and ask it to evaluate it, it will likely crash:

Stockfish 5 64 by Tord Romstad, Marco Costalba and Joona Kiiski
position fen 4k3/4p3/8/8/8/8/8/3KP3
go depth 14
Segmentation fault: 11

But you could use a Python library such as Chessnut to validate moves. Chessnut returns all legal moves with get_moves() and raises an InvalidMove exception if you pass an illegal move to apply_move(), as shown in their example:

from Chessnut import Game

chessgame = Game()
print chessgame  # 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1'

print chessgame.get_moves()
"""
['a2a3', 'a2a4', 'b2b3', 'b2b4', 'c2c3', 'c2c4', 'd2d3', 'd2d4', 'e2e3',
 'e2e4', 'f2f3', 'f2f4', 'g2g3', 'g2g4', 'h2h3', 'h2h4', 'b1c3', 'b1a3',
 'g1h3', 'g1f3']
"""

chessgame.apply_move('e2e4')  # succeeds!
print chessgame  # 'rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1'

chessgame.apply_move('e2e4')  # fails! (raises InvalidMove exception)

You could update the game each move with Chessnut, and only pass moves to Stockfish for evaluation if Chessnut says they're valid.


Good books to learn Sveshnikov Sicilian I'm a club player around 2100 FIDE rating trying to learn the Sicilian Sveshnikov, with the black pieces, for long time controls (2 hours/game). What books do I need to read in order to learn this opening properly?

Themes I would like to see in the books:

How to deal with most common variations
Possible transpositions
Ideas in middle game
Pawn structure and how to approach it
Traps to be aware of
Common endgames

I think one of the best books on the subject has been written by Rogozenko.

The Sveshnikov Reloaded explains the ideas very well with plenty of textual analysis and not only pages of long variations with only Informant type evaluation symbols. I have the book at home (even though I mainly play Najdorf and accelerated Dragon Sicilians), and I remember that one of things that pleases me most in this book is Rogozenko's clear explanations of the subtleties of move order tricks.

The first edition is a bit outdated and might run into refutations, especially in the tactical lines (such as the bishop sacrifice line). But if I am not mistaken there is a "recent" (2012?) second edition.

It is the Quality Chess edition. According to me, one of the best editing houses around.


Longest sequence of mutually forced moves In this position, the black move 1. ... Qc3 results in two consecutive forced moves, Kxc3 and Ke7:

2rkr3/2p5/2q5/8/8/8/3KP3/3R4 b - - 0 1

1... Qc3 2. Kxc3 Ke7

What is the longest sequence of mutually forced moves that can be constructed on a standard chessboard?

Assuming you allow promoted material (since you didn't say anything :-),
this (on Page 13 of the PDF) is the (unfortunately, extremely unknown) finite record since ages. It shows the record for the longest sequence of only 1 legal move for each side, with use of promoted material.

[Title "Karl Scherer, Feenshach 1980, Page 13"]
[FEN "BQ4R1/2Q5/3Q4/4Q1pp/5B1P/6QK/Rrrrrrrq/R4nk1 w - - 0 1"]

1. Qxh2+ Rxh2+ 2. Bxh2+ Rxh2+ 3. Qxh2+ Rxh2+ 4. Qxh2+ Rxh2+ 5. Qxh2+ Rxh2+ 6. Qxh2+ Rxh2+ 7. Rxh2 g4+ 8. Rxg4+ hxg4+ 9. Kxg4 Kxh2


As a Class B, how do I improve my chess against A level or higher? I been playing bunch of tournaments where I have solely played against Class A. I keep losing or drawing against Class A players. I draw when I'm winning. Sometimes I don't understand A players moves in the middle game. I struggle understanding what plan a given position needs or what plan my opponent has in mind. Even if I figure out their plan, I play the wrong move to stop them. Sometimes I'm winning, but A players have really strong counter-play and I lose to their counter-play. My endgame is my strongest feature, but I usually get to a losing endgame. Any advice?

Silman's How to reassess your chess book is invaluable. Give it a thorough reading if you haven't yet.

My advice would be

Replay your game with an engine. Find out the moves you did wrong.
if most are tactical, then train yourself on that
if most are positional, then find out what imbalances are there at your move. Read relevant chapter in the book (could be just the summary section) and see if you can find a better move.


How do I respond to 8. g3?! in the 4. e3 Slav? This is taken from a rapid game where my opponent threw me by playing 8. g3, coming out of book in the 4. e3 Slav:

[FEN ""]
[StartPly "17"]

  1. Nf3            Nf6
  2. c4             c6
  3. d4             d5
  4. e3             Bf5
  5. Nc3            e6
  6. Nh4            Bg6
  7. Nxg6           hxg6
  8. g3

I didn't keep a gamescore (it was at work during a lunch break), but I remember at this point I could think of no constructive plan at all (I played 8...Bb4 and ended up playing 2 knights vs. 2 bishops with a cramped game).

My question is, what should black have played on move 8 and why?

I see no reason to ?! mark. 8. g3 is good book move and standard way to limit opponent's play with open h-file. The most flexible move by far is 8...Nbd7 after it. After 9.Bg2 dxc4 should be good. But again, 4...Bf5 is no refutation of slow Slav and 5...Bg6 is in my opinion less challenging than 5...Be4, while there's nothing wrong with 8.g3. Don't expect you have guaranteed equality in this line. Once I played the NN vs. BB game in similar line and it is suffer, even if computer says it is OK. I was always somewhat worried about 4...Bf5 as white, but as black, I played 4...Bg4 every single time :-)


Are there any gambits involving sacrificing a piece? My impression of the word "gambit" is the sacrifice of a pawn or several pawns at the opening stage of a chess game. However, based on the definition on Wikipedia, a gambit (from ancient Italian gambetto, meaning "to trip") is a chess opening in which a player, more often White, sacrifices material, usually a pawn, with the hope of achieving a resulting advantageous position.
The phrase "usually a pawn" seems to imply that a gambit could be a sacrifice of other pieces. Am wondering what are examples of gambits that sacrifice a knight, or a bishop, or a rook, or even the queen, or a combination of these pieces?
I am not talking about blunders at the opening stage that cause loss of material. I am asking about openings that stand the test of time where one side willfully sacrifices some material other than pawns to earn some advantage.
A related question: What is the "biggest" gambit that is still being played at the master's or above level? That is, a gambit that white sacrifices a combination of biggest value of pieces and yet obtained enough advantage development and/or space; at the same time, the game is somewhat acceptable for black as well.

This is kind of out there (virtually nobody plays it as white and even fewer allow it as black) but there is a rather crazy queen sacrifice line in the Grand Prix:

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 "]
1.e4 c5 2.f4 d5 3.Nf3 dxe4 4.Ng5 Nf6 5.Bc4 Bg4!? 6.Bxf7+ Kd7 7.Qxg4+ Nxg4 8.Be6+ Kc6 9.Bxg4

5...Bg4!? by black is quite rare and combative, inviting (daring) white to initiate the festivities where 5...e6 instead is calmer. So white takes it up and sacrifices the queen for just two minors and the hope of long-term play against black's lack of development. Yes, there isn't any quick tactical win, just long-term pressure while down a queen.

The position has occurred several times in master play (check the lichess database) but is extremely rare, and most examples not recent. It was even featured on chessgames.com many years back: http://www.chessgames.com/perl/chessgame?gid=1648780


Playing d5 in the Pirc defense Two days ago, I played, a game as Black and after the analysis I was quite surprised to see that the computer suggested, in several moves throughtout the game, the move d5. In this position I think Black should develop first with g6 (what I played) and solve the situation in the center later.

I think the justification for this move is that it dismantles White center but I am not sure why it should not wait until later in the game.

As Black, I always try to keep a pawn on e5 (in this case) on c5. Can someone confirm this and explain me the Pirc Defense idea behind this?

Thanks in advance.

In most early-stage Pircs, black is slightly worse, so of course, the computer will prefer any move that equalizes, or in this case, gives you a slight advantage.

White is not well-placed in the center due to the pin on the Nf3, and the Bd3 interferes with the Qd1's protection of the center (d4) too. Black can effectively "blow-up" the center here, which leaves him at least equal.

It comes down to specific tactics here, and d5 works. If you wait, white may play d5, and your opportunity would be lost.

One more note: I do not play e4, so I don't think about this much, but in many e4 openings, black wants to get in the equalizing d5, thus you don't usually see the bishop on d3 since it makes d5 easier to achieve. It is usually on e2, c4, or b5, so Bd3 was probably not best. In d4 openings, which I play, Bd3 is common, but black already has d5 in, so it is fine.

  [FEN ""]

  1. e4 d6 2. d4 Nf6 3. Bd3 e5 4. c3 Bg4 5. Nf3 Nc6 6. Be3 d5 7. Nbd2 (7. exd5 Qxd5 {The black queen is now well-placed, and threatens e4.}) 7... dxe4 8. Nxe4 exd4 9. cxd4 Nxe4 10. Bxe4 Bb4+ 11. Kf1 $15


Why is ChessBase calling this a draw? The above image is clearly not a draw. Why is ChessBase giving this errant line?

After I play 10...Kd6!! Now White is winning. Why is ChessBase giving this error?

Has the position after 10....Kd6 occurred earlier in this game? If yes, the engine thinks it's a repetition and shows "0.00".

More information on the repetition issue can be found on this thread on TalkChess, a forum dedicated to computer chess.


Opening systems for White which enable queenside castling In general, as White, I prefer to castle queenside and then start attacking with a kingside pawn storm. Every time, I hope that my opponent lets me do it.
For instance, when I play 1. d4 (or 1. c4), I hope my opponent does the King's Indian so that I can go to my Saemisch setup with queenside castling. Similarly, when I play 1 e4, I hope my opponent plays the Sicilian so that I can go for the Yugoslav or English attack.
However, in both instances, Black has to cooperate to let me castle queenside. For instance, with the Slav against 1 d4 or 1...e5 against 1 e4, it becomes difficult for me.
Hence, in general, is there an opening system for White where I can go queenside castling irrespectivly for how Black plays? The closest that comes to this seems to be the London system, but I haven't deployed it much in my games. I am mainly a 1. c4 player (and play 1. e4 occasionally when I know that my opponent might play the Sicilian).

The London System is unlikely to be your answer, as white almost always castles kingside.  If you want to castle queenside, then 1.c4 is really the last way you should be playing, as white rarely castles queenside in openings where the c-pawn is moved early.

On the whole, I'd say 1.e4 is probably your best bet, as the Sicilian is the most common reply, when queenside castling is possible in most variations with Be3/Qd2/f3 setups.  It is also usually possible against the caro-kann and scandinavian in the main lines (although black often castles queenside too), and also the pirc/modern.  Against the french you can play the classical with 4.e5, which often features opposite side castling, or the Reti Gambit.

Against 1.e4 e5, I think it's better to play main lines, but you can pretty much get a sharp queenside castling position by force in the Centre Game, where the main line is something like 1.e4 e5 2.d4 exd4 3.Qxd4 Nc6 4.Qe3 Nf6 5.Nc3 Bb4 6.Bd2 0-0 7.0-0-0. Objectively, black is fine, but most opponents will not be prepared for it and you may catch out a few people who think the Centre Game is bad and do not play seriously against it.

Not sure about rarer lines like the Alekhine defence, 1...b6, 1...Nc6, and such, but in my experience you don't face that stuff very often.

Of course, I cannot really recommend such a single-minded approach.  It's better for your game if you play all types of positions, and you can often attack with same-side castling.


Can a 2000 ELO rated player teach me middlegame play properly? I have reached 2500 in the chess.com tactics trainer while I haven't study theory and my FIDE rating is 1637 (I reached 1930 in rapids a year in France).
I want to study with a coach and there is one at my club who knows a lot of openings and endgames theory but is rated only 2000. Is his rating a limitation to teach me? I guess I need lessons not only in openings and endgames but in middlegame play. Should I search for a better trainer out of my club or it is enough that this coach train me?

Is his rating a limitation to teach me?

No.
As I say in this answer, "you are too fixated on rating". High rating does not guarantee coaching ability. Low rating does not preclude coaching ability.
Today the guy in our club who does the most coaching is rated about 1900. 50 years ago, the first time we played for the same club, he was rated about 2150. He has coached a surprisingly large number of the players in our region who are now rated 2100-2300, although they moved on to better high level coaches before they got to those levels.
It is always interesting to watch him play one of his former students. Is the student going to give him a draw for old time's sake? Or crush him? If they give him a draw then afterwards the coach in him will tell them why they shouldn't do that while also saying "Thank you!"

I need lessons not only in openings and endgames but in middlegame play. Should I search for a better trainer out of my club or it is enough that this coach train me?

We don't know the trainer so we haven't a clue. Probably the best approach for you is to have a trial lesson and see what you think. Did you learn anything? Was it worth it?
Taking a trainer is not like getting married. If you find it is not helping you then you can just stop and walk away.


Rule enforcing a player to move on a turn? I'm an amateur chess enthusiastic and I have a somewhat esoteric question about the rules of moving on a turn. In chess, is there a specified rule that a player must move a piece during her turn?

I realize that in a chess game, there is no reason to not move a piece. But I'm designing puzzles relating t o chess and whether this rule exists matters for the puzzle.

Yes, there is a rule that a player must make a move during her turn. If the player in turn has no legal moves and her king is not in check, then the game is drawn.

  I realize that in a chess game, there is no reason to not move a piece.

Actually, almost all chess endgame theory, and thus a huge part of the whole game of chess is based on the fact that a player has to move a piece during her turn. I'll explain this by a simple example and some handwawing. Consider for example the following endgame:

[title "White to move and win"]
[fen "4k3/8/4K3/4P3/8/8/8/8 w - - 0 1"]

1. Kf6 Kf8 2. e6 Ke8 3. e7 Kd7 4. Kf7 Kd6 5. e8=Q

If, at her 4th move, Black didn't have to move the king, the game would be drawn, as there is no way for White to promote her pawn. However, because Black king has to step away, White gets a new queen and wins the game. (Note that this does not mean that a king and a pawn always win against a lone king; very often the game will be drawn, because also White has to make moves she would not want to make.) A situation like this, where having the turn actually makes your position significantly weaker, is called a zugzwang; for more examples, see for example the Wikipedia article

This and more complex endgames are the reason why one pawn advantage is often enough to win: You can exchange pieces until you get to an endgame where you can then often convert the extra pawn to a win. Very often the winning technique of king and pawn endgames are based on the fact that the winning side can force the losing side's king to step away from defending important squares simply because the king cannot stay on the best square forever. The winning technique of many other endgames is then based on the fact that the winning side can threaten to convert to a winning king and pawn endgame, restricting the options the losing side has.


Should you let your opponent know if they have forgotten to press their clock? I'm in two minds here.

The good sportsman says you should always let your opponent know (maybe limited to once per game).

The more hard-nosed part of me says that managing the clock is part of the game and rules like anything else. If you are playing seriously then you should treat the clock no differently to for example, the 'touch-move' rule and expect no help from your opponent.

Does it matter whether one is playing a club game or a tournament with prize money at stake?

In my personal opinion, if you have noticed that your opponent has forgotten to hit their clock, the unwritten rules of good sportsmanship dictate that you should advise your opponent of such. It can become distracting to both players, though, if you have to do this more than twice.

So the real question comes down to the legal technicalities.

Are you even allowed to make your move before your opponent hits his/her clock? The USCF rules, at least, are not very clear about this. But it does not seem to be illegal at all. Many people feel it is bad form to move before your opponent has pushed the clock, but such a rule would be unenforceable from a practical perspective.

What about in sudden death? Tournament Directors and Arbiters are generally directed to not interrupt the game to point out illegal moves when in sudden death. So even if this were a rule, it likely would be set aside in sudden death.

Other than information about time delays and time controls here is what the USCF says about the clock:

6.) Except for pressing the clock, neither player should touch the clock except:
   6a.) To straighten it.
   6b.) If a player knocks over the clock a penalty may be assessed.
   6c.) If your opponent’s clock does not tick you may press his side down and
        re-press your side; however, if this procedure is unsatisfactory, please
        call for a director.
   6d.) Each player must always be allowed to press the clock after their move is made.
   6e.) A player should not keep a hand on or hover over the clock.

Back in 2008 there was a bit of a controversy about these questions regarding the clock. For the most part things have just been left up in the air. So in summary, it is not your responsibility to advise your opponent, many people feel it is good form to do so. But if it appears that your opponent is habitually forgetting to press the click, I would just continue on with the game and not advise him or her more than twice. There is no reason that this should interfere with your enjoyment of the game and ability to concentrate. Ultimately, in the USCF, the rules put the onus on the individual to press his own clock.

Kasparov v. Karpov, 1987 (pointed out by Tony Ennis) from the AP Archives

  For almost three minutes, members of Kasparov's delegation looked on
  helplessly as his time slowly ticked away. Under the rules, neither
  they nor the match arbiter could warn Kasparov of his mistake. When he
  finally noticed, Kasparov had less than a minute left for 14 moves. As
  he desperately played move after move, Karpov closed in with a
  crushing mating attack. "It's really a very bad psychological shock,"
  Spanish chess writer Fernando Urias said. "Kasparov has not only lost
  right at the start of the championship, but he also lost playing with
  the advantage of white."


Who did Nigel Short really play on the ICC in 2001 when he thought he was playing Fischer? In 2001, Nigel Short went public with the opinion that he had in fact played Bobby Fischer on the Internet Chess Club.
This was denied by Fischer himself, and the consensus seems to be that it was not in fact Fischer that he was playing. However, though I have the impression of reading something about who Short was really playing some time ago, I cannot remember this for sure and now cannot find a conclusive source on who Short's opponent actually was. Has there ever been a definitive statement on this?

Nobody knows who he played, because nobody has come forward to take credit; however, some chess sleuths compared the moves against various engines and found that there was considerable evidence to support a particular engine (I believe it was called "blitz tiger") as the mysterious Fischer.  Because of the incident where Short chatted with Fischer, there must have been a human behind the account as well (many accounts on the ICC are run entirely by computers without any human interaction at all).  The ICC can probably do some user profiling to figure out who the player is either by comparing the location/IP/e-mail to another user or by doing some internet forensics based on information they gathered from the incident.  However, it seems like they either don't care or if they did find out, they don't want to share (based on what xaisoft said) so it will probably always be a mystery.  And, to be honest, it's a better story that way, and because all this is is a good story, that's a good thing.


Why queen traps happen so frequently? I am aware that in most chess games the king is the one to be checkmated. Yet when playing many online chess games I have found the queen is the the one being checkmated. Is this simply another variation of chess?

The short answer: because it is the most valuable piece after the king.

The long answer:
For a piece to be trapped two things must happen: you need to threaten to capture it, and you need to make this in a way it can't escape or be protected without loss of material or a positional drawback suck as mate.

For a piece to be protected effectively, the piece attacking it must be more valuable than the piece being attacked, so any piece can attack the queen and if there is a trade the attacker will gain a material advantage. So other pieces can be protected in more ways than the queen.
For a piece to be able to escape, it must be able to move, and it needs a safe square. The queen is the most mobile piece, but moving in straight lines, it can be easily blocked by another piece, and any piece can do this, since a trade would mean material loss for the defending side. So the queen can be blocked in more ways than most pieces. For a square to be safe for the queen, it needs to be free from attacks (except from the opposing queen), again, since any trades that happen after the queen moves to that square will result in material loss. Other pieces can move to squares attacked by stronger pieces, if the defender has another piece protecting that square. So the queen has less safe squares available than most pieces.

That sums it up, but there are MANY exceptions when you take into account the actual position, since a square can be safe if moving to that square uncovers a discovered attack with a mate threat, or many other situations.


Always losing to the same opponent? I am just asking if anyone here suffers a problem of always losing to the same opponent. This problem occurs to me so often against one particular player. Well, the story goes like this:

When I first played chess, I met a chess player, let him be A. At first, my chess skills are lower than his and I always lose to him (this is normal). But then as my chess skill progresses, even if I can beat other players (let them be B), I still can't beat A.

So here's an absurd situation of A beating me, me beating B, B beating A.

I have to emphasize, this situation occurs every time. And by B, I mean every other club player, but not A. A is not a particularly good player, but somehow I just cannot manage to beat him.

The question I am asking is whether this is occurring to you all and how can I overcome it

Is this a psychological problem, as his opening repertoire is normal for me?

Thanks!

We were all there, it is normal.

It is a psychological problem, but without 3+ sample games there is nothing I can do to help you. If you could edit your post with 3+ games that illustrate typical scenario, I could engage in solving your problem with greater effect.

Without the games the best I can advise you is :

Know your opening -> ask here if you need help;
know how to play your middlegame pawn structure ( isolated pawn / d4 vs c6 + e6 / sicilian formations... ) -> ask here if you need help;
Make smart exchanges in the endgame -> ask here for help by posting the endgame position;

To cut it short, work on your technique and this problem will solve itself. As for psychological aspect of this problem, keep your nerves calm when you reach good / winning position, as that is the point when "mind tricks" will start to mess you up.

This is especially true when you reach winning position, the "victory rush" will loosen your sense of danger and you might miss opponent's saving tactics. Even if the game is still won for you, the psychological blow it will make will be devastating and will shake you so much that you might lose the game in the next move ( happened to me countless times ).

This is not the case when you play other opponents because your mind is calm, and you are able to control "victory rush" by carefully and objectively assessing the position. This is the place that you must work on hardest -> keep your emotions under control during the game and assess position objectively.

As soon as you feel fear that you will "f*ck it up" because he's lucky or destiny chose him to punish you for your chess sins, STOP PLAYING. Take 1 minute to breathe and calm down. This is the crucial moment in the game, so use that 1 minute to calm down -> no thinking, calculating, assessing lines, NO! Just breathe and calm down, that is all you need ( you can always spare a minute even in blitz games ). Tell yourself "I've got this!" and just aim not to lose the game. Your main goal is not to lose, so even if you draw the game in an overwhelmingly won position for you, it is still a success as you broke the losing streak. In your mind he will no longer appear as "SuperChessMan", but after not losing that game he will become simply yet another player. The moral boost you will feel in that moment will disperse all the previous psychological barriers and you should be able to engage him successfully in the next game.

Another thing that helped me was analysis of my own games against such opponents. You should always do this when you lose the game, always! Just turn on the engine and see its suggestions, that is enough for a start. You can always post your game here for help, we don't bite people's heads off! :)

For now, this is all the advice  I can offer.

Good luck!


How or what to practice when mentally exhausted? You had a long day and your batteries are drained. You would like to improve your chess though. How to do this in an appropriate or maybe even restorative way? Should you practice at all or do something else instead?

I found myself blundering away in games or tactical puzzles and moved away from it to look for better ways. How or what do you guys practice if your mentally exhausted?

Edit: Thank you for your answers!

Yoga.

Failing that watch your favourite TV programme.


Chesscademy Tactic: Is my alternative as good as the right answer? I've been playing with the Chesscademy app for a while, solving some tactics (which I'm not sure is improving my chess, but it's a good puzzle to kill some time). Today I ran into one tactic that I failed to solve, though my play seemed to result in the same advantage as the one picked as an answer.

Since I'm a beginner at Chess, I might be missing something about the move that makes it a better candidate, so I decided to post it here and get some opinions.

Below is the move that the tactic claimed is right (Black then White):

[FEN "r1r4k/1p5R/3b4/4q3/B3P1Q1/1n1P3P/6P1/5R1K b - - 0 1"]

1... Kh7 2. Rf7 Kh6 3. Qh4 Qh5 4. Rh7 Kh7 5. Qh5+

My answer was basically the same, except instead of 3. Qh5 Rh7 I played 3. Qh5 Rf6.

So I could foresee one outcome from that play:

[FEN "r1r4k/1p5R/3b4/4q3/B3P1Q1/1n1P3P/6P1/5R1K b - - 0 1"]

1... Kh7 2. Rf7 Kh6 3. Qh4 Qh5 4. Rf6 Kg7 5. Qh5 (Kf6 6. Qh6)

That opens up an X-ray attack on the bishop if the King captures the rook (5. Kf6 Qh6), though it can be easily defended if the king goes to a square next to the bishop.

Is there any reason why this play is worse than the original answer? Usually, when I thought I was right about a play I'd think for a while and find some reason why it was not a good one, but this time I'm not really figuring out why the original answer would be better than this one.

The problem is that 5. Qxh5 isn't check, so Black has time for some back rank tricks (instead of capturing the rook on f6):

[FEN "r1r4k/1p5R/3b4/4q3/B3P1Q1/1n1P3P/6P1/5R1K b - - 0 1"]

1... Kxh7 2. Rf7+ Kh6 3. Qh4+ Qh5 4. Rf6+ (4. Rh7+ Kxh7 5. Qxh5+) Kg7 5. Qxh5 Rc1+ 6. Qd1 Rxd1+ 7. Rf1 Rxf1#


At what point does this mental trick stop working? Sometimes, I'll be in a position where my opponent is threathening to do something and I cannot stop it. So, in response, I play a move that looks pretty dangerous and clever, but which I in fact have not managed to calculate all the way through and I have no idea whether it will work or not.

And I often see that in such situations, the opponent becomes overly paranoid and thinks I've just played some sort of mastermind move, and then they start retreating or playing too defensively or whatever, and I manage to weazel my way out of the situation.

When I then go back and analyze my play with the engine, it will often tell me that my clever move was a complete mistake and my opponent wins by just doing the obvious thing they were about to do.

At what point do these mental tricks, where you make dangerous-looking movies to make your opponent overly paranoid, stop working? I'm thinking there must be some point where players simply become too good to be fooled by that sort of trickery, and just calmly make decisions based on pure calculation.

I currently play in the 1600-1700 range on lichess.

This trick is prevalent in all levels. Of course, depending on the position, your ability to muddy the waters varies. Against much higher rated opponents, it is typical that they will  gain an advantage without giving you much counterplay. Nevertheless, in all levels of the game, the losing side will try to muster some counterplay to get back into the game.
You make a comment about moves that look dangerous but are not. The higher rated your opponents are, the more likely they will realize that your plan is not dangerous. Often, it will be better for the losing side to defend and wait for the right time to strike than to go all out on a dubious plan. Furthermore, many positions, even in the top levels, can be wildy complicated to calculate, and the objective evaluation is not always a good predictor of outcome even at the top levels. Thus, not even grandmasters will always be able to evaluate the position accurately from "pure" calculation.
So to answer your question more precisely and perhaps unsatisfactorily, if you make a dangerous looking move, if it is "obvious" to your opponent that it's unsound, you'll be punished. Where "obvious" depends on the strength of your opponent and the subtleness of your clever move.


UCI undo move command? I checked the UCI specification here and I don't see a way to undo a move. I'm using stockfish, is there a way to do this?

For example, how would I accomplish the following:

position startpos moves e4c5
undo

With the intent of the above "undo" to result in a position of e4

Unfortunately the UCI protocol is stateless, there is no way to ask the engine to undo a move. The protocol is designed for communication between GUI and engine, you are supposed to have your own board representation such that you can update the engine.

For example, you would need to do:

position startpos moves e4c5
position startpos


Is c5 a key move in an opening where white begins with d4? In one game between world class players, (Alekhine and Rubinstein), the game began  1. d4 d5 2. c4 e6 3. Nf3 ...

When Rubenstein played 3... a6?, Alekhine grabbed the opportunity to reply  4. c5! because a6 was a "wasted" move and 2) weakened b6. This was the case even though it is usually not good for White to release the tension on d5 so early. (Alekhine won.)

In this game between amateurs, the game appears to have been decided by Black's 14th move 14. ... Nf8, and the fact that White could play c5 on move 18 (after exchange of several "forced" moves). I lost a game without making tactical mistakes; how can I avoid this happening in the future?

On the other hand, I was told that if Black can play c5 against d4 without adverse consequences, he equalizes. Which is why I advised Black to play 3... b6 in the game in the previous paragraph, to prepare for an eventual c5.

Is it true that in a game where White opens d4, the result of the game is largely determined by who gets to play c5?

First of all, 3...a6 after 1.d4 d5 2.c4 e6 3.Nf3 is not a terrible move for Black. It has been played by many top-level grandmasters, including Morozevich multiple times. 4.c5 is historically the eighth most common move in that position (4.cxd5 is the most common), so it's not like it refutes 3...a6. Opening theory has moved on since Alekhine.

To the more general question: putting a pawn on c5 in 1.d4 d5 positions changes the position a lot, played either as White or as Black, so it's always worth considering.

For Black, ...c5 is one of the primary ways to try to break up White's strong center based on d4. It can be easier to engineer than the other possibility, ...e5, because his dark-squared bishop is already supporting it. He can also play supporting moves like ...Nbd7, ...Qc7 (both of which are also useful for preparing ...e5), and ...Rac8. Often Black's early play is based on creating the opportunity to play ...c5; if he can get it in without problems, he's usually doing well. Note also that ...c5 is an incredibly important move in the French, again trying to pry open d4.

For White, c5 is fairly rare. It does gain space on the Queenside, but its main drawback is that it releases a lot of pressure on Black's d5 pawn. This means that his e6 pawn isn't as necessary to support it, which makes it a lot easier for him to play ...e5, since he doesn't have to worry so much about having lots of support for both the new e5 pawn and the suddenly-less-defended d5 pawn. Generally it is considered that the cons of c5 (removing pressure on d5 so that ...e5 is harder to stop) outweigh the pros (gaining space on the Queenside).

One exception is the Chebanenko Slav (1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 a6), where 5.c5 is a quite common move. One extra thing it has going for it here is that it highlights the weakness of Black's b6 square, and it's going to be a bit difficult for Black to play ...b6 to engage with it. In the game you mention, Alekhine probably had a similar idea regarding the weakness of the b6 square after 3...a6.

(18.c5 in the game you link to had nothing to do with any of this; that move is good because it entombs the bishop on b7.)


Longest forced win after 3 moves It is possible to reach (exactly) #8 after just 3 moves:
[Title "#8 after 3 moves"]
[FEN ""]

1. e3 f6 2. Qf3 Kf7 3. Nh3 Qe8! 4. Ng5+ Kg6 5. Bd3+ Kxg5 6. Qf4+ Kh5 7. g4+ Kh4 8. Qg3+ Kg5 9. f4+ Kh6 10. g5+ fxg5 11. Qxg5#

Is there any longer forced win than #8 that can be reached (and proven) after just 3 moves?
This question is a variant of, and therefore not a duplicate, "The quickest mate in n."

After playing around in the Lichess's analysis page for some time, I have found a mate in 10. Throwing the moves into chess.com's analysis page provides further confirmation. It has some wholly unique lines, and only a few dualed lines, making it reminiscent of a chess problem, per @Hauke Reddmann's above comment.
[FEN ""]
[Title "#10 After 3 Moves"]

1. e4 d5 2. h3 Kd7 3. Bb5+ Ke6 {Now the helping play is over.} 4. Qg4+ Kd6 5. e5+ Kc5 6. b4+ Kxb5 7. a4+ Kb6 8. a5+ Kc6 9. b5+ Kc5 10. Ba3+ Kxb5 11. Nc3+ Kc6 12. Qa4+ b5 13. Qxb5#


How do I find people to play chess with me through correspondence? I really would like to play chess, nevertheless, I do not have access to physical chess players. My question is, how do I find people to play chess with me by email? I have not been successful in finding anyone yet. I would like to play against a human, as I would like to practice AN, and that I think that a human is more interesting to play against. The computer is rather boring...
   Also, I would be interested in playing Chess Variants, such as Hex Chess. People who play such seem to be even more rare.
   In conclusion, I need help on how to find someone to play against, not only chess, but chess variants. As for the variants, I would be happy to know how to access them online or download them, as well.
   Thank you! I look forward to learning these things.

I have never been particularly interested in correspondence chess, but the internet is full of chess servers. On many of them can you play correspondence chess:

http://en.wikipedia.org/wiki/List_of_Internet_chess_servers

Here is a similar question, with a possibly useful answer:

Best websites for correspondence chess?


How does one prepare for a big chess tournament? The Chicago Open is in four days. Assuming a player continues his daily regimen of reading chess books for a few hours and playing two, perhaps three slow games (60/5, at least) a week, what else should a player be doing?

Also, should a player stop this regimen before the tournament to "clear the mind"? If so, how many days before?

Regarding openings

I'm completely confident in the middle game. Everyone says that opening study should be reserved for when I'm higher rated (~2000).

This is true, because by following general strategy, I can transition into the middle game easily. With a plan, it's hard (if not impossible) to go wrong.

Why, then, does everyone advise to review openings before a tournament? (I have taken perhaps a brief look at the classical variation of the Ruy Lopez, but that's it.)

Eat your carbs, get up at a time such that you'll be most alert during the games, maybe play a few blitz games to go through your opening repertoire. Move around according to your level of physical activity, because you're going to be sedantary for a long time.

Playing long, proper games is exhausting if you're really focused throughout, so you don't want to play any extra games just before the event. Reading chess books at a time so close to a tournament has its parallels with cramming before an exam: it pays off if you're faced with something relevant, but could cost some precious mental energy.

Be rested and stop training long enough so that you feel ready on the day of the event. For some, one day is enough, others may need over a week.

On an indirect note, fatigue usually starts to set in after 4 rounds or so; physical endurance is actually important here. While it's a little too late to address this now, if you find yourself making incredibly careless mistakes in the later rounds, you'd want to consider adding a physical part to your regime if you're serious about the game.


Leela Chess PUCT Mechanism How do we know w_i which is not possible to calculate using the tree search only?

From the lc0 slide, w_i is equal to summation of subtree of V ? How is this equivalent to winning ?

As you noted, w_i is not calculated by the search tree. It is simply the number of wins out of the total simulations performed at that node (if this is the method used to score the node). This scoring mechanism is also known as playout.


Can Black save this Knight vs Bishop endgame with a pawn down? After playing horribly in the opening, my opponent played a couple of suboptimal moves which suddenly allowed me to exchange some pieces and get the following unclear position.

I thought about giving the h pawn away, giving White two potentially
useless h pawns if he captures gxh4. However, I thought that making
use of it would require trading my g pawn for the White f pawn, which
seems to be impossible.

[White "Villain (2200)"]
[Black "Hero (2000)"]
[fen "2B3k1/5pp1/4pn2/8/3P3p/4P1PP/5P1K/8 b - - 0 1"]

1... Ne4 2.Kg2 hxg3 3.fxg3 *

The position after fxg3 was when I needed to formulate a plan. I thought of several options, all of which are more or less passive defenses, as I think moving my pawns would only weaken them and gain nothing in any position.

First idea: Leave my king on g8, and sacrifice the knight to get a fortress.
More precisely, force White to move his pawn to g6 and trade the
knight and f7 and e6 pawns for White's other pawns  (king, pawn g6,
light-squared bishop vs. king g8, pawn g7).

[Event "Draw"]
[fen "6k1/6p1/3K2P1/8/4B3/8/8/8 b - - 0 1"]

However, I didn't see any
way to force this: if White can keep any pawn not in g6, he wins if I sacrifice the knight.

Second idea: Leave my king to protect the g pawn. This forces White to exchange
the e pawns. Then I can use my king to stop the passed d pawn and my
knight to stop the kingside pawns. However, from what I calculated (and analyzed afterwards), it seems it is not sufficient. This is just an example
of what I think could happen; I haven't checked every move thoroughly, but the general idea is still the same: Black can block
White's d pawn, but White can always force a win due to Black
knight's limited mobility and zugzwang.

[White "Villain (2200)"]
[Black "Hero (2000)"]
[fen "2B3k1/5pp1/4p3/8/3Pn3/4P1PP/6K1/8 b - - 0 3"]

3... Nd6 4.Ba6 Kf8 5.Bd3 Kg8 6.Kf3 Kf8 7.e4 Kg8 8.d5 exd5 ( 8...Kf8 9.e5 ) 9.exd5 Kf8 10.Ke3 Kg8 11.Kd4 Kf8 12.Kc5 Ke7 13.Kc6 g6 ( 13...f6 14.Kc7 Ne8+ 15.Kc6 ) 14.Kc7 Ne8+ 15.Kc6 f5 16.g4 fxg4 17.hxg4 g5 18.Bg6 Nf6 19.d6+ Kd8 20.Bf5 Ng8 21.Kd5 Nf6+ 22.Ke6 Nd7 23.Kf7 Ne5+ 24.Kf6 Nc4 25.d7 1-0

During the game I remembered that KBPvKN with the advanced pawn can be a win in some positions. However, I didn't remember when that happens, and I also couldn't see
any way to force the exchange of all kingside pawns before allowing White to advance his pawn this far. In post mortem, I was able to blitz a win against the opponent in a position similar to this (without the g pawns), even though he claimed it is an easy draw.

Third idea: Use my king to stop the d pawn, exchange my e pawn to White's d or e pawn and force him to defend the isolated pawn so he can't make progress. This is what I decided to do in the game, making by endgame skills look ridiculous.

[White "Villain (2200)"]
[Black "Hero (2000)"]
[fen "2B3k1/5pp1/4p3/8/3Pn3/4P1PP/6K1/8 b - - 0 3"]

3... Kf8 4.Ba6 Ke7 5.Bd3 Nf6 6.Kf3 Kd6 ( 6...e5 7.dxe5 Nd7 8.Kf4 Ke6 9.Bc4+ ) 7.Bc4 Nh7 8.h4 Nf6 9.g4 Nd7 10.g5 f6 11.Kg4 Nb6 12.Bb3 e5 13.gxf6 gxf6 14.h5 Ke7 15.h6 Kf8 16.Kf5 1-0

Something like 6...e5 was my idea but I couldn't make it work in any position. For example, after 6...Kd6 7.Bc4, I realized the f7 pawn would hang. I saw no other way to make my position any better: any pawn move would weaken them and any king move would give White more space. Only after 13.gxf6 I realized that my plan of moving king to stop the d pawn allowed White's king to break through easily.

Question: Did I miss something? Was one of these plans drawing after all, or is there a resource I didn't see, or is the game simply lost?

I think it is good to notice the possibility of different fortresses, like the one you mention, and of course the wrong coloured bishop for the h-pawn. But to turn reaching such a fortress into a "plan" is way to early in this position.

I think fxg3 was probably ok. At the first glance it looks ugly that now there are white prospects for a passer on the d-line and on the h-line, but your g and f-pawns can actually deal with the white g and h-pawns. Against g4 and h5 you should play f6 and against h4 and g5 (like in the game) you could have played g6. These setups prevent an h-passer.

But maybe 10.f6 was still ok. Then you certainly should have played 11…fg 12.Kg5 Nf8 which prevents the intrusion of the white king. But even here h5-e4-e5-h6 and Kf6 might just win for white.

An engine will be able to come up with better lines, but my feeling is that

Keeping your pawns compact.
Keeping the white king away.
Preventing a h-passer.

might have earned you a draw. (Coincidentally you violate all these guidelines with the move e5, after which you are surely completely lost.)


Crazyhouse Chess: Playing with a real board and overall popularity? Played a decent amount of bughouse but only started with crazyhouse a month or less ago. Although on the surface very similar games, I would say they are fundamentally different because there is no partner and so crazyhouse is "deterministic." I think that bughouse must be more popular if only because all that is required to play are two boards and two standard sets whereas crazyhouse is much better suited to online (I guess you could have bicolored pieces to play live.) So is crazyhouse catching on at all? Has anyone seen a set that would allow playing live? (I note there is not yet a tag for crazyhouse.)

Very boring answer: when I was at the university, we used to play it on a real board with two sets of pieces. Whenever you take a piece, you exchange it with one of the correct color.


Popularity of the Scotch Game I was looking back at a game played between Hikaru Nakamura and Magnus Carlsen at the 2017 London Chess Classics in which Hikaru employed the Scotch game and played very creatively getting a winning advantage at one point. In the end, however, he failed to win it and the game ended in a draw. If any of you haven't seen it yet, I recommend to check it out since it's a real bloodbath!

There have also been many great players who have used it such as Garry Kasparov who never lost a single game with it! I have been wondering why it isn't used at the top level for a long time, but never got a chance to ask it. Could someone please explain why it isn't used at the top level?

I think you are on to something, and statistically, there is a very good reason to play the Scotch over the Ruy Lopez, but that might not be all there is to it.

I think that the main reason is that we are taught that the Ruy Lopez is THE most classical opening, and is the best. I have seen that mindset in SO many books written by the top players over the years, in particular, Karpov. Also, I was watching "Method in Chess" videos recently, and GM Dorfman said that white is statically better because white has more space, and black is confined to three ranks, and white can play on the kingside, center, or queenside, and thus, black must always be on the lookout. I think that is just what classical Soviet players were taught, and that mindset has not been broken among the elite, especially since so many of them became trainers in other countries after the breakup of the Soviet Union.

Statistically, you are right on the money.

All the top players I looked at had similar results to Kasparov, meaning an overwhelming plus score with it. I left out Anand, Aronian, So, MLV, and Grischuk from the following list since they played it so few times (less than 6 each), it was clear that their reason was simply surprise.

Carlsen 11-1-6 (wins-losses-draws) 78%
Caruana 5-0-6 72%
Nepomniachtchi 34-6-29 70%
Nakamura 13-6-7 63%

These are against all players, and the problem is that in Carlsen's case, in particular, is most of the games were from when he was not the Carlsen we know today, and I could have left him out. Caruana's games were virtually all against elite competition!

Then I decided to search only for all games in the Mega 2020 database with players both above 2700, and then the stats fell dramatically down to a typical winning percentage for white, 58% even (53-25-97, 175 games total).

When I then did the same thing for 2700 players playing the Ruy Lopez, there were 2366 games with a breakdown of 580-373-1412, or only 54%.

That is still a healthy plus for the Scotch, but maybe the Soviets still were right, and that the only reason the stats for the Scotch are so good is that the opponent was not expecting it as much. Also, I did not attempt to look at hundreds of games to identify where the games where lost. It might have just been due to other circumstances.


Chessbase products - difference Since the ChessBase website is rather unclear, I would like help regarding a few issues:

I have a few questions.

What is the main differences between the Big Database and the Opening Encyclopedia?
Does the Opening Encyclopedia require purchase of ChessBase separately, or is it a program in of itself?
Does either of these below products require a DVD player or is there a downloadable version?
ChessBase, Big Database, Opening Encyclopedia

Big Database is a large (6.8 million) collection of unannotated games. Opening Encyclopedia has slightly fewer games (probably games of lower quality are left out), but also contains 6000 opening surveys, 85 000 annotated games, and opening articles from older issues of ChessBase Magazine.
It seems Opening Encyclopedia comes with ChessBase Reader 2013 included. This lets you access the whole content of the Opening Encyclopedia, but it doesn't have the full functionality of ChessBase 14. With the Reader you cannot modify the bases or add your own games and analysis.
All the products you mention are available to buy and download from ChessBase Shop.


Please help me understand the f6 break in the French defense I'm really struggling to understand this move to be honest. Even after carefully reading a similar question posted here, I still just don't get it and, more importantly, when it's good to play the f6 break. I apologize if that seems stupid.
Can someone explain it in very clear and simple terms for me please? Is it just for making a semi-open file for the rook? Getting rid of white's e pawn? I'm a little unsure about this topic.

The f6 break is a key idea in the French defense, and the point is mainly to add more pressure to White's center. In the French, one basic line of thought is the following:

Let White occupy the center
Destroy White's center
Occupy the center yourself
Win the game, as White now will be totally helpless!

If black manages to complete steps 1-3 outlined above, without significant material losses or a serious weakening of the king's position, step 4 will indeed often be possible to accomplish.

Let us examine the move f6 in view of the steps above. If White has a pawn on e5 and black plays ...f6, it's possible to

a) take on f6
b) defend the e5 pawn
c) ignore it

a) If Black hasn't castled, it most likely means that Black will have to respond to this with ...gxf6. Black now typically has pawns on e6 and on f6. It is not hard to see that Black can have plans to push ...e5 in the near future, and if the pawn capture on f6 hasn't left Black's king open to direct attack, it's possible that Black will achieve steps 2-3 outlined above shortly.

If Black has castled, on the other hand, more options than ...gxf6 will be available. Often either a knight, bishop or a rook could also take on f6 in this case. In case of rook capture, Black has a semi-open f-file for his/her rook. Taking with a bishop adds more pressure on the a1-h8 diagonal. Taking with a knight adds possibilities to play ...e5 to free the black bishop on c8 in some cases. It is clear that the ...f6 break by Black has given many possibilities for future plans.

One more note: If White takes the pawn on f6, the h2-b8 diagonal will be ripe for the black bishop to occupy, often coupled with a queen on c7. This is sometimes very unpleasant for White.

b) If White protects the pawn, Black has some other options with ...f6 played. If White has played f4, Black could sometimes take on e5, and if White recaptures with the f-pawn, it can in some cases be possible to play ...Qh4+ for some concrete tactical purpose. Other times Black can be perfectly happy with just trying to take over the f-file and pressure White's position that way. If White recaptures with the d4 pawn instead of the f-pawn, Black has the option to open the diagonal a7-g1 with ...c4, or play ...d4 and just try to break once again in the center, to activate his/her pieces.

If White has played f4, and it's not good for Black to take on e5, Black can wait, and try to maneouver the c8 bishop to g6 via Bc8-d7-e8-g6. This is a standard plan in the French defense to activate that light squared bishop. Or Black can lock the center with ...f5 in some cases, to stop White from attacking the black king. In rare cases, after White has played f4, Black can even try to play ...g5, to again just try to break up White's center. This can be very risky, so it's not often the first idea Black thinks of, but it should never be forgotten, as it can recieve a great pay-off if well executed.

If White guards the e5 pawn with Bf4, the g5 break is more natural, and Black can even try to go for a kingside pawn storm in some cases. Again, it has to be well executed, as it can easily expose Black's king. Otherwise it's more typical for black to keep the tension in the center, and let White make the big decision to alter the status quo. However, at every move, White has to be wary of possible alterations of the center. The same is usually true if White defends e5 with another piece.

c) This option is very rare, and can only be considered if White manages to create an enormous treat elsewhere on the board that black needs to deal with immediately. If this is the case, the ...f6 break may be a bad idea. Otherwise, if White ignores the ...f6 break, Black can usually just take on e5, and normally having a knight on c6 and a queen on c7 (and maybe even a knight on d7 in some cases), this can mean that black simply wins a pawn.

This reply got much longer than I originally had intended it to be, but I feel like most of the reasons why Black may consider playing ...f6 in the French defense are in here. Remember that I have not included any concrete examples here, and that it all depends on the position. If ...f6 is an obvious blunder, for some reason I failed to mention here, it should of course not be played.

TL;DR: ...f6 is about challenging White's control over the center, and trying to open up the position for Black's pieces.


What is the point of delaying the exchange in the Rossolimo? [fen ""]

 1. e4 c5 2. Nf3 Nc6 3. Bb5 g6 4. O-O (4. Bxc6) Bg7 5. Re1

Is there any point in maintaining the tension? Does it force any adjustments from Black? Is the timing irrelevant or is White really waiting for something?

The underlying reasons for delaying BxN are -

Preserving options
Saving tempi

Suppose in the final position black plays a6 forcing white to make a decision. Bf1 is a perfectly good alternative to BxN. It is one which will lead to an entirely different game, one which white may prefer.
In any case it makes some sense to wait for black to commit with a6 because then BxN comes without the loss of a move that playing it unprovoked would involve and it has provoked a weakening of the b6 square.
Again looking at the final position above, an immediate BxN leaves black with a choice of recaptures, either bxc6 or dxc6. White may not like the position after dxc6, in which case it makes sense to wait until black plays d6 first before exchanging. Alternatively white might not like the possibility of BxN bxc6 followed by d7-d5. Again if white waits for d6 then a tempo has been saved.
Keeping options open and saving time are features of the way stronger players play. Prematurely closing down options and squandering tempi are what weaker players do.