A tool to search for certain moves played Is there a tool to display how many times a certain move has been played?
Note that I do not mean openings, I mean specific moves. Moves that I am looking for would be castling with checkmate or underpromotion to a knight with checkmate, and similar things. Is there a tool available to search for something like that?

Chess Query Language operates on PGN files of games and does what you want as well as much more powerful stuff. It is a free download. There are lots of examples to get you started here.


Claiming a 50-move draw with a mating move Under FIDE law 9.3.1, a player to move may claim a 50-move draw by writing down the intended 50th move and making the claim.

Supposing this claim is otherwise valid;  if the move would checkmate then is the game drawn?

Mate ends the game immediately, but the mating move must be made, not just written down. If the player only writes the move down and claims a draw in the correct way, it's a draw (but I doubt it'll ever happen in practice).


What are the most common checks in chess? I read somewhere that to optimize move generation for a chess engine it's good to have fast detection of position where one side is checked (to eliminate illegal moves).
The author suggested that check detection could be improved slightly by having the code test for common checks which happen first. However, they didn't give anymore insight than that.
I reasoned that my code for check detection should look for checks coming from the opponent's side of the board. Other than that though I couldn't think of anything else. This lead me to ask the following question:

What are the most common checks which occur in chess?

For example, are checks from queens more likely than checks from knights? Are certain diagonals more prone to checks than files?
Advice for methods I could use to answer this question in the comments would also be appreciated

What are the most common checks which occur in chess?

Back rank checks (and check mates) must be the number one. I would suspect that bishop checks from h2/h7 on the castled king should also be up there in the top 10 if not number two.


Should beginners learn some boring drawn games first? I recently studied the game Aronian vs Caruana in the Sinquefield Cup 2016, and I was absolutely delighted ! Unlike most GM games, it made total sense to me. I understood why the pawns were moved, why the bishops and knights were developed, how both sides had isolated pawns. I understood how the pressure slowly built around these isolated pawns and counted the number of defenders and attackers each side had around these pawns. I understood how the exchange took place, I understood how the pawns had to be placed on squares on the opposite colour as the opponents bishop and most importantly I understood why it was a draw (usually I don't) !

I was taken in by the beauty of the balanced positions and the web of Defense and attack.

Imagine my surprise when I saw their post match interviews. Aronian said he was not well, and although he was ashamed of the match was happy with the draw. Caruana said he jinxed it by saying that all his matches with Aronian have been interesting the day before, and that's why their match wasn't interesting.

Is this match considered boring because they played out old lines ? As a beginner it's new to me, and I actually understood it.

That's why my question is if beginners should first learn some of these standard boring lines so they can understand all the principles involved ? And if so, please recommend some sources where I can do that ?

The game mentioned above goes as follows:

rnbqkbnr/pppppppp/8/8/3P4/8/PPP1PPPP/RNBQKBNR b KQkq d3 0 1
1. d4 Nf6 2. c4 e6 3. Nf3 c5 4. e3 a6 5. Nc3 d5 6. cxd5 exd5
7. g3 Nc6 8. Bg2 Bd6 9. dxc5 Bxc5 10. O-O O-O 11. Nd4 Nxd4
12. exd4 Ba7 13. Bg5 Be6 14. Rc1 Rc8 15. Bxf6 Qxf6 16. Nxd5
Bxd5 17. Bxd5 Rxc1 18. Qxc1 b5 19. Qc6 Bxd4 20. Qxf6 Bxf6
21. b3 Rd8 22. Rd1 Kf8 23. Kf1 a5 24. Bf3 Rxd1+ 25. Bxd1 Ke7
26. a4 bxa4 27. bxa4 Bc3 28. Bb3 Bb4 29. Ke2 Kf8 30. Bc4
1/2-1/2

Yes understanding gm games is a very wonderful feeling. To understand many of the plans that occur in high level games I would suggest reading Pawn Structure Chess by Soltis. It's a book describing plans inherent in the position based on pawn structure, something all top GMs use in their games.

The reason why Aronian and Caruana considered this game boring is 2 fold. 1) the pawn structure was pretty much symmetrical. They each had a,b,d,f,g, and h pawns, and their d pawns were identically placed in the center. Their really aren't pawn structure plans in such positions, leaving a lot less resources to push your opponent around. Also it's a lot easier to create an advantage in a position with imbalances and asymmetry for both sides. 2) Secondly many of the pieces were exchanged when Aronian took on f6, leading to a very equal endgame with no chances for a win. Not to mention it was an opposite colored bishop ending, which are notoriously drawish.

Hope this helped!


Help needed with a chess dilemma How can I get a checkmate in three moves?

[FEN "8/2R5/1B1k4/2R5/3N4/1K6/3p4/8 w - - 0 1"]

[FEN "8/2R5/1B1k4/2R5/3N4/1K6/3p4/8 w - - 0 1"]

1.Kc4 d1=Q 2.Rd5#

So two moves, not three.

The first thing to note is that the Black King cannot move.  The second thing to note is that (most) non-forcing moves by White will allow Black to Queen the pawn - with check.  This fails the challenge.

Experimentation will show that moving the Rook on c7  (for example R7c6+) allows the King to escape to d7 or e7. The other frcing move is Rd7+ but of course that isn't helpful.  Since the c7 Rook is protected by the Bishop, we can try moving the other Rook.  We have to find forcing moves, so the first one I see is R5c6+. But this lets the King escape to d5 or e5.  Another forcing move is Rd5+ but the Black King would eat it. But it's so close to checkmate.  There's no forcing move with the Bishop.  The Knight has 2 forcing moves, but neither seems to help.

So we move the White King to c4 to support the Rook we intend to put on d5.  This has the additional benefit of not costing us a tempo if Black queens the pawn.  That realization is fundamental here.  The White Knight blocks the Queen from capturing the Rook on d5.


How to take advantage of under-development of opposing pieces? Gambit openings are usually based on sacrificing pieces to have much better piece development.

Some gambits, like Queen's gambit, or King's gambit, I can understand the idea. However, I cannot evaluate Danish gambit. White sacrifices two pawns, has two developed bishops, but Black seems to be able to cover up pretty fast.

[fen ""]
1. e4 e5 2. d4 exd4 3. c3 dxc3 4. Bc4 cxb2 5. Bxb2

Although it is obvious that Black has no piece development, how can White play to take advantage of it?

This is an example for how it can go wrong for Black side.

[Event "?"]
[ECO "B02"]
[White "Jacques Mieses"]
[Event "Monte Carlo"]
[Black "Frank James Marshall"]
[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/ b - - 0 1"]

[Setup "1"]

1.e4 e5 2.d4 exd4 3.c3 dxc3 4.Bc4 cxb2 5.Bxb2 d6 6.Ne2 Nc6
7.O-O Be6 8.Bd5 Nf6 9.Qb3 Qc8 10.Nf4 Nd8 11.Bxf6 gxf6 12.Nh5
c6 13.Re1 Be7 14.Qf3 Rg8 15.Nxf6+ Bxf6 16.Qxf6 cxd5 17.exd5
Rg6 18.Qh8+ Kd7 19.Nc3 Bxd5 20.Qe8+ Kc7 21.Nxd5+ Kb8 22.Rac1
Nc6 23.Rxc6 1-0


Which piece combinations can mate a lone king without being aided by the attacking king? Clearly not a practical question since the king can and should be used in the endgame, but I was curious if anyone has done a comprehensive analysis of which combinations of pieces (including some unrealistic combinations) can force a checkmate against a lone king in a pawnless endgame without being aided by their own king. Let's just pretend the attacking king doesn't exist (or maybe, as a looser restriction, tuck it in a remote corner where it might be allowed to make waiting moves).

There are some easy combinations that can force a checkmate:

queen and any other piece
two rooks

On the other hand, there are these classic endgames where it is possible to mate with the help of the king, but not without it:

queen
rook
two bishops
bishop and knight

It seems to me that the following combinations of pieces can force a checkmate:

rook and two bishops
two bishops and two knights
four bishops (two pairs!)

And the following don't:

rook and bishop
rook and knight (you can mate, but can you force it?)

But there are many other combinations I haven't looked at in detail yet:

rook and two knights
rook and knight and bishop
two bishops and knight
two knights and bishop
three knights
three bishops
four knights
...

Possible
queen and any other piece
The queen can on its own push the king to the edge of the board by following it  a knight-distance away and making use of zugzwang. Once on the edge, it is easy to bring the second piece and mate with the queen in front of the king. The only exception would be if the second piece is a pawn on the next to last row
Example for a knight (similar for any other piece).
3k4/3Q4/8/4N3/8/8/8/4K3 w - - 0 1

two rooks
Well known lawnmower mate.
rook and two bishops
Easy mate. Two bishops cover the escape route of the king while the rook checks from the side. Sample game to demonstrate the method:
8/8/8/8/3k4/8/6RB/6KB w - - 0 1

1. Re2 Kd3 2. Re8 Kd4 3. Bf4 Kd3 4. Bf3 Kd4 5. Rd8+ Kc4 6. Be3 Kc3 7. Be4 Kc4 8. Rc8+ Kb4 9. Bd5 Kb5 10. Rb8+ Ka5 11. Bc5 Ka6 12. Bc6 Ka5 13. Ra8# *

two (opposite colored) bishops and two knights
Easy mate. Push the king to the edge of the board where the two bishops can jail the king on two squares. Then take those two squares with the two knights.
[FEN "8/8/8/8/8/3k3K/6NB/6NB w - - 0 1"]

1. Nh4 Kd4 2. Bf4 Kc4 3. Bf3 Kb4 4. Be5 Kb5 5. Be4 Kc4 6. Ngf3 Kb4 7. Nd2 Ka4 8. Bd6 Kb5 9. Bd5 Ka6 10. Bc6 Kb6 11. Bd7 Kb7 12. Nc4 Ka6 13. Bc6 Ka7 14. Bc7 Ka6 15. Nf5 Ka7 16. Nfd6 Ka6 17. Ne5 Ka7 18. Nd3 Ka6 19. Nc5+ Ka7 20. Nc8#

Two pairs of (opposite colored) bishops
Very easy mate. Four bishops cover lots of squares and it is even possible to mate the king in the middle of the board.
[FEN "8/8/8/8/8/3k3K/6BB/6BB w - - 0 1"]

1. Bf4 Kc4 2. Be4 Kc3 3. Bge3 Kc4 4. Bhf3 Kb4 5. Be2 Ka3 6. Be5 Ka4 7. Bc5 Kb3 8. Bb5 Ka2 9. Bc4#

rook + bishop + knight
Easy mate. Similarly to rook and two bishops you can cover the escape squares while the rook checks from the side.
[FEN "8/8/8/8/3k4/7K/6NR/7B w - - 0 1"]

1. Nh4 Kc3 2. Nf5 Kb3 3. Rd2 Kc4 4. Be4 Kb4 5. Rc2 Kb3 6. Bd3 Kb4 7. Nd4 Ka5 8. Rb2 Ka4 9. Bc4 Ka3 10. Rb6 Ka4 11. Nc2 Ka5 12. Ra6#

rook and two knights
Easy mate. Similar to the king+rook mate, you can create a box with one knight protecting the rook. You have the second knight free to take further squares from the king and thereby make the box smaller. Mate is similar to rook + two bishops or rook+bishop+knight with the rook checking from the side and the knights taking away the escape squares.
[FEN "8/8/8/8/3k4/8/6NR/6NK w - - 0 1"]

1. Rh3 Ke5 2. Rh4 Kd6 3. Nf3 Kc5 4. Rd4 Kb5 5. Ne3 Kc6 6. Rd5 Kc7 7. Nd4 Kb6 8. Nc4+ Kc7 9. Rd6 Kc8 10. Nb5 Kb8 11. Rd7 Kc8 12. Rh7 Kd8 13. Ne5 Ke8 14. Nd6+ Kf8 15. Nf5 Kg8 16. Rh6 Kf8 17. Rh8#

four knights
Easy mate. Keeping the knights together you take lots of squares and it is easy to push back the king and mate him.
[FEN "8/8/8/8/3k4/7N/6NN/6NK w - - 0 1"]

1. Nf2 Kc4 2. Nhf3 Kb4 3. Nf4 Kc4 4. Nge2 Kc5 5. Nd2 Kd6 6. N2d3 Ke7 7. Ne4 Kd7 8. Nd4 Ke8 9. Ne5 Kd8 10. Nd5 Ke8 11. Nd6+ Kf8 12. Ne6+ Kg8 13. Nf6+ Kh8 14. Ndf7#

Impossible

queen or
rook or
two bishops or
two knights or
bishop and knight or
rook and bishop

There is not even a theoretical mating position for these.
rook and knight
There is a theoretical mate (Arabian mate), but it cannot be enforced. For an analysis see this question
two (opposite colored) bishops and knight
This is not obvious. Let's just look at the potential mating positions. You can easily convince yourself that the only way to mate is if the king is in the corner (let's say in a8, similarly for other corners) and if the mate is done by a bishop (along the a8-h1 diagonal) while the other bishop and the knight cover the escape squares b8 and a7. I can see three fundamentally different mates. (other mates are mirror symmetric or differ only in the distance of the bishops so are essentially the same).
k7/B7/8/1N6/4B3/8/8/8 w - - 0 1

or
k7/8/N7/8/3BB3/8/8/8 w - - 0 1

or
k7/3N4/8/8/3BB3/8/8/8 w - - 0 1

Doing a small retro-analysis, you see that in all cases the last move was Be4+ and that bishop came from somewhere along the b1-h7 diagonal.
What was black's last move?

If the king came from a7 or b8, it could as well have gone to b7 in the last move (note that b7 was not covered by any piece since the light squared bishop came from the h7-b1 diagonal). If it went instead of a8 to b7 there was no mate possible.
If the king came from b7 in the last move, it was not forced to move to a8 either since at least one of the squares c8 or a6 were available as well.

So in summary, there is no forced mate with two bishops and a knight.
three bishops
Similar argument as with two bishops and a knight. You easily convince yourself that (theoretical) mate is only possible if the king is in the corner of the color of the single bishop. If there are two dark squared bishops and a light squared bishop, there are essentially two different (up to symmetry) mating positions on a8:
k7/B7/8/8/3BB3/8/8/8 w - - 0 1

or
k7/8/8/8/3BBB2/8/8/8 w - - 0 1

In either case, the last white move was Be4 and that bishop came from somewhere along the b1-h7 diagonal.
If the king was before on a7 or b8, it could have gone to b7. If the king was before on b7 it could have gone to c8 or a6. In any case there is no way to force the king to the corner and mate him.

Impossible but no analytical proof yet

two knights and bishop
three knights

For a proof by computer analysis see the answer below by Vaclav Kotesovec.


Should I play a risky combination when I don't see the refutation? I've read in a book that one should play a line if (s)he thinks it is decisive and let the opponent proves that (s)he is wrong.

But what about playing a (risky, by risky, I mean that I am not sure) combination when I don't see the refutation?

The trouble I have with sacrificing when I am not sure is that if I am wrong, the opponent will win without effort, just by answering to my moves.

Here is an example of a game that I saw a combination (18. a5), but I didn't play it because I was not sure enough (and it turned out to be good):

[FEN "r4rk1/1b3pb1/pq2pn1p/1pn3p1/PQ1N4/2N1P1BP/1P2BPP1/R2R2K1 w - - 3 18"]

1. a5 Qa7 2. Ndxb5 axb5 3. Nxb5 Na6 ( 3... Qa6 4. Rd6 Nfe4 5. Rxa6 Nxa6 )
4. Qe7 Qc5 5. Qxb7

By the way, my ELO is around 1900.

It depends on how well you like your chances without the combination.

If, taking everything into account (material, position, opponent's rating, etc.), you are likely to win the game in the normal course of events, then play it safe.

On the other hand, if you have lost material, or are in a bad position, or your opponent is rated much higher than you, take a chance.


More Optimal Computer-Found Moves I am looking for examples of scenarios where the believed-best moves among experts were proven wrong by a computer.

This might not be quite what you're after, but computer-generated endgame tablebases have revealed new knowledge that includes overturning previously held beliefs about the evaluation of certain endgames. This means that the experts were wrong about what the best moves were at plenty of points in such endgames. As an example, it's noted in the endgame study section of Wikipedia's tablebase article,

  For instance, the endgame with a queen and bishop versus two rooks was thought to be a draw, but tablebases proved it to be a win for the queen and bishop, so almost all studies based on this endgame are unsound.

That article cites John Nunn's Secrets of Pawnless Endings for that fact, and Nunn's whole Secrets of ----- Endings series would probably be a good source for more examples of this sort of evaluation turnaround, as those books are the end result of Nunn's extended exploration of tablebases.


Algorithms to score chess moves How to score a chess move, which techniques are used to figure out how good a move is?

Firstly, I would like to point out, you cannot figure out how good is the move, because no move can improve position, only make it worse. And the winner is usually the one who managed to "destroy" his position less than the opponent. So the questions should be: "how bad a move is"... =)

Secondly, I believe you cannot actually score a move. You can only score the original position and the resulting position and subtract the former from the latter  to find out how worse it became.

The position evaluation is quite big and complicated topic by itself. There are two ways -- static evaluation, when you just add up all pieces and some extra points for open lines, centered pawns and other things considered to be "good", and dynamic evaluation, when you start building a move tree, as far as you could, statically evaluate positions after a few moves and use min/max to derive the evaluation for the current position.

If you are interested, there are quite a few open source chess engines, starting from 100 lines of code, written in C, C++, Python and other languages, so you may easily choose the one you like and see how it works, maybe change a few lines and see what happens.


What is "Rook Box" and its use? When I once watched a chess game on television, one player use a trick named "Rook Box" to draw a game. I didn't understand its move and so, I want to know what is "Rook Box" in chess.

I know it's a good trick for making a game draw.

Well, it is as simple as encasing a rook in a virtual box. We'll take the example and see it.

 [Date "????.??.??"]
 [Result "*"]
 [FEN "1k5r/1P3K2/8/2p2p2/7p/4P3/8/3R4 w - - 0 1"]

1.e4 fxe4 2.Kg7 Rh5 3.Kg6 Re5 4.Kf6 Re8 5.Kf7 Rh8 6.Kg7

We see that the rook is trapped inside a 4x4 box. Losing the rook means losing the position, and the only way not to lose it is to stay inside the box, and be constantly pushed by the king. If White doesn't do so, he is in serious trouble.


What happened to the official website for the World Chess Championship 2010? The official website for the WCC2010 is supposed to be (and previously was) located at (please do not visit the page until you read the whole post): http://www.anand-topalov.com/.

Now, unless I am very mistaken, the persons appearing on the above web address at this particular moment, do not look much like Anand or Topalov (protagonists of the WCC 2010). Nor does the content look to be related to chess (well, at least not to how I see chess).

I do not understand the language or the script, but from the pictures it seems that the new main topic of the site is breast enlargement. This leads me to believe that the site has been hacked.

Does anybody know where to report this sort of thing? Is there another copy of the website, on some other location?

Apparently, FIDE didn't renew the site, so somebody purchased it. You can check the old contents at http://web.archive.org/web/20100701000000*/http://www.anand-topalov.com


A book on the Lasker - Capablanca World Championship Match (1921) Recently I've been studying Lasker - Capablanca World Championship Match (1921). Is there a book that gives the story behind the match? Also, I would appreciate the game annotations.

Best wishes and thank you.

Capablanca's comments about the match can be found in this book.


Is the TSCP chess engine able to run on a 32 bit processor? I'm a beginner learning about chess engines and would like to find a chess engine written in C (like TSCP) that doesn't use bitboards for board representation because I want to test the engine on a 32 bit processor. Though I can tell TSCP doesn't use bitboard, I'd really appreciate it if anyone can clarify for me if TSCP requires a 32 or 64 bit processor to run. Thanks!

Although pretty much everything even a mobile phone runs on the 64 bits, there is no reason why TSCP can't be run on a 32 bits architecture. In fact, it was written before 64 bits became common. TSCP can be run on any architecture as long as you can compile it, there is no platform-dependent code.

Bitboard is simply a 64-bits integer, that doesn't mean you can't use it on a 32-bits machine. Your machine would need at least an extra instruction cycle to transfer a 64-bit integer on a 32 bit machine, but everything still works.


Does playing bughouse have any benefits on your chess game? I've heard that it helps your tactical skills, but can a chess variant really help you in tactics more than simply playing standard chess.

Bughouse really doesn't. What can help you is shogi. Shogi is similar to chess but with complications that start almost immediately and become much more crazy than in chess. The reports that I have had from multiple players who went from chess, to shogi, back to chess is that the chess tactics suddenly seem exceedingly easy when you return.

To speculate for a moment, bughouse is harmful because it is similar enough to chess that it interferes with your thinking about chess. Shogi is sufficiently different to be separable.


Is this endgame position a draw? It’s white to move.

[FEN "8/8/8/3k3p/3P3K/2P3R1/8/7r w - - 0 1"]

I was white, and this was a blitz game which ended up as a draw because I didn't know what to do. My friend and I later analyzed this position, and he suggested that if I had played Rh3! here, then I would've won (of course, if black trades rooks, white wins). But I wasn't convinced, as the trade wasn't forced at all, and judging by the black king's position, I thought black could hold with perfect play (i.e. keep his king where he is, and use rook checks/occupation of the f-file to stop the white king from getting too close to the white pawns). We gave up analyzing after a while, and used an engine to check the position, and it gave +3 to white, which would imply (I think) that there is a forced win. But machines still tend to be wrong, and after my friend played out the line given by Fritz 12, no progress was made by white. The black rook simply occupied the f-file, and the white king couldn't get close to the white pawns.

Is this a draw? If this isn't a draw, how can white win?

Yes, it seems to be drawn. First consider the following variation, but in particular the position after 2.Kxh5 first:

[FEN "8/8/8/3k3p/3P3K/2P3R1/8/7r w - - 0 1"]

1.Rh3 Rg1 2.Kxh5 Rg8 3.Rf3 Kc4 4.Kh4 Kd5? 5.Rf5+!

Here we don't even need to consult an engine because there is a better oracle to be had. This 6-piece position is covered by existing endgame tablebases, and you can confirm with a query that this is drawn. So we know for a fact that going this 1.Rh3 route leads to a draw. (White could try delaying the pawn capture and making a more productive immediate move, but it doesn't help, and just leads to play like that coming after 1.Kg5, discussed at the end below.)

As to the idea behind Black's play from here, it is to keep the pawns at bay with the king, and as you intimated in your original post, to use the rook to cutoff the white king as much as possible. It's difficult to say much more about the exact drawing method here, because the play can be very complicated (one reason to love endgames, by the way). To give an idea, consider the position after 4.Kh4. 10 of Black's possible moves keep the draw (including those that simply move the rook along the g-file), but the perhaps seemingly harmless 4...Kd5?, putting the king back where it was, is suddenly a loss for Black in 41 moves, but only if White plays 5.Rf5+!, as all other fifth moves again draw. One way to get a good feel for the correct and incorrect play (and for the general notion of how impenetrable optimal play in technical endgames can be) is to toy around with moves at the link I gave above.

White's only other first move option is 1.Kg5, and it's not too surprising that this draws if winning the h-pawn immediately already draws. It's true that White avoids getting his king cut off on the h-file, but the cost of leaving Black with a distracting outside passed pawn is too high. The point is that the black king and rook can easily stop the pawns if the white king isn't helping out his rook. But now if the white king does try to get involved, say via ideas like Kf6-e6 and pushing the d-pawn, Black can keep things level because she has her own passed pawn to play with.


Moving a piece out of the way for check I was recently told you may not move a piece out of the way of a second piece to allow the second piece to put the other player in check.  For example, I have my queen and rook lined up on a diagonal with my opponent's king.  I move my rook, opening the path for my queen to their king putting it in check.  According to my opponent, you aren't allowed to do this. You have to actively move the queen into a check position.

Is this a standard rule?

You can move your other piece to make your queen attack the king in a normal position such as:

4r3/8/8/2QB1k2/p5q1/3K4/8/8 w - - 0 1

1.Bf3+**[Discovered-Check]
(1.Be4+**[Double-check])

But you are forbidden to do so if the piece you move will put your own king in check, such as:

3r4/8/8/2QB1k2/p5q1/3K4/8/8 w - - 0 1

1.Bf3**[illegal-move]

Here both Be4 and Bf3 are illegal because the rook on d8 will be attacking your King.

So to conclude, there is no standard rule avoiding you to play discovered check except when the move puts your own king in check.


What makes a chess puzzle hard to solve? A couple friends and I built a mobile app (Chess Puzzle Blitz) where we allow people to compete for fun or money solving chess puzzles.
We have a pretty large puzzle database but are always adding to it.
One thing we keep iterating on is the types of puzzles we surface (currently only mates 1 through 5 (usually 1->3). For example, one feedback we got early on is that black puzzles are harder because of the mental switching between puzzles (so we rate black puzzles harder in that context).
For you, what makes a chess puzzle a good puzzle and what elements make them hard/frustrating?

Each player has his own form of tactical blindness, so "what makes a problem difficult" varies from solver to solver. If one of the key moves is backward-going, I'll never find it.
Some players forget that when they move a piece within their calculation, it no longer covers the squares it did before.  Some players have a hard time counting multiple exchanges on the same square. Different for all.
"Black puzzles are harder" is silly. Chess pieces are only light and dark for convenience. The pieces could all be the same shade of gray, and chess could still be played as long as the players remembered which gray pieces belong to which player.
When it's "Black to play and win", flip the board so Black's on the bottom of the diagram, and you will find them just as simple to solve.


Depth problem in stf 12 I don't understand something about depth in STF 12, in fact i thought it was basically the number of anticipated half moves, but when I run it, I sometimes have results with higher depth and less moves, for example:
info depth 48 seldepth 51 multipv 1 score cp 23 nodes 19440223582 nps 9584151 hashfull 1000 tbhits 0 time 2028372 pv e2e4 e7e6 b1c3 d7d5 d2d4 g8f6 e4e5 f6d7 c3e2 c7c5 c2c3 d8b6 a2a3 b8c6 b2b4 c5d4 c3d4 a7a5 b4b5 b6b5 e2c3 b5b6 g1f3 b6d8 f1d3 f8e7 c3b5 f7f6 e5f6 d7f6 e1g1 e8g8 f1e1 c8d7 c1f4 f6e4 f4c7 d8e8 d3e4 d5e4
has 40 half moves anticipated while
info depth 43 seldepth 47 multipv 1 score cp 28 nodes 7457369869 nps 9860163 hashfull 1000 tbhits 0 time 756313 pv e2e4 e7e6 d2d4 d7d5 e4d5 e6d5 g1f3 g8f6 f1d3 c7c5 c2c3 f8e7 e1g1 e8g8 h2h3 b8c6 f1e1 f8e8 c1g5 h7h6 g5f6 e7f6 d4c5 e8e1 d1e1 d5d4 d3e4 d8e7 e4d5 e7e1 f3e1 c8e6 d5e6 f7e6 c3d4 f6d4 b1c3 a8d8 a1d1 d4c5 d1d8 c6d8 e1f3
has exactly 43 half moves anticipated
The opposite can also happen beacause i found on the net (however not in stf12):
info depth 65 seldepth 97 multipv 1 score cp 8 nodes 17288598093977 nps 9446437 hashfull 999 tbhits 0 time 1830171180 pv c2c4 c7c5 g1f3 b8c6 d2d4 c5d4 f3d4 g8f6 g2g3 e7e5 d4b5 f8b4 c1d2 a7a6 b5c3 d7d5 c4d5 f6d5 f1g2 c8e6 e1g1 d5b6 c3a4 b4d2 g2c6 b7c6 a4b6 d8b6 d1d2 e8g8 d2c2 f7f5 b1c3 f5f4 c3a4 b6a7 a4c5 a7f7 c5e6 f7e6 c2e4 f8f6 b2b3 f6h6 a1c1 e6h3 e4g2 h3e6 c1c4 a8d8 f1c1 f4g3 h2g3 d8d2 c4c6 e6c6 g2c6 h6c6 c1c6 d2a2 g1f1 g8f7 c6c7 f7f6 f2f3 a2b2 c7a7 b2b3 a7a6 f6e7 a6a7 e7f6 f1f2 b3b2 f2e3 f6g6 a7a6 g6g5
which has a 78 half moves anticipated.
Could you explain me where it comes from?
Thanks!

A chess engine's depth used to denote how many half moves it calculates ahead (roughly speaking), however this has long not been true anymore. Traditionally you would search one depth at a time, so first 1 ply deep, then 2 plies deep, then 3 and so on, each iteration increasing the depth by one ply. Modern engines however have various search heuristics which lets them search deeper in relevant positions and less deep in less important positions. Because of that, the iteration counter that is still called depth there, is hardly representative of the actual depth of the main line. (also of course the depth of the different calculated lines can be very different)
One thing that (AFAIK) still counts for something is the "seldepth" number, which denotes the deepest line looked at. However that number too is not too relevant, one line being calculated very deeply doesn't necessarily tell much about the other lines.


Color-coding moves and games If you are familiar with watching chess broadcasts on ChessBomb, you'll know they have an engine running on the server which evaluates moves, and colors each move according to whether (according to SF) it was the correct move, an imprecise move, a mistake, a blunder etc. with colors ranging from bright blue (good) to bright red (bad). When switching to a game, one can then instantly see how well the game was played, and where a blunder/mistake may have occurred.

Does anyone know if a similar feature is available in other chess software or websites where one can upload their own games? And get such color codings for their own games?

I'm only looking for something equivalent or very similar to this; I know some software uses graphs to display the +/- score as a function of the move number, and some software can auto-analyze all moves and annotate it with ? and ?! and such. I'm not looking for that.

Edit: below is an example of what I mean, when viewing a game in the mobile browser. It instantly shows all the moves and highlights which moves were good/bad.

Here's how color-coded analysis looks on the lichess desktop site.

As you can see, depending on the severity of the error (according to Stockfish), different colored bars pop up on the game analysis - blue for an inaccuracy, orange for a mistake, and red for a blunder. A black bar will show if a player loses a forced checkmate sequence or blunders into a forced checkmate sequence. I don't have the app, currently, but I believe that the same thing shows up there, since I used to play exclusively on the app.

You get this color-coded analysis by clicking "request a computer analysis" - it's on the bottom of the screen on PC.

If anyone has the app downloaded at the moment, feel free to screenshot this feature and add it to this answer.


Engines that predict the outcome of current matches in real-time I'm looking for an engine that will allow a full game to be loaded in an attempt to visualize the major turning points in the game. Are there engines that predict the outcome of current matches in real-time?

Any chess program (Crafty, for instance) will do that.  Use analysis mode.  Key in the move, and it will produce a score.  The score implies how well one side is doing.


What type of a chess player am I? I'd like to know what sort of a chess player I am. Am I too much of an attacker, or a defender? Or maybe, a little bit of both? On the contrary, I enjoy attacking and deploying stealthy tactics but I'd like to know from you guys, what KIND of a player am I?

Here are two games from which you can tell my style. In the first one, I play as white and in the second, black. (Note that both of the opponents were defeated due to resignation)

[First]

http://en.lichess.org/TB2LHLZi#0

[Second]

http://en.lichess.org/TZGTdIyr#0

So there it is; now what do you think?

Here are two games from which you can tell my style.

How could anyone judge something like this basing on two games? Imho those games aren't good examples at all. Those weren't any tactical, sharp games and not positional ones for sure. Your opponents just blundered. But you have taken adventage of it, so you're perceptive, that's good for you:) A bit offtopic: I'd suggest you to learn some openings, I've got a feeling that you don't have a solid repertoire.


Games with two knight promotions in them Games with two knight promotions are extremely rare, but a few have existed. In an article of his, Tim Krabbe stated that, about the game Zurakhov - Koblentz, "This is one in only 5 games with two serious Knight-promotions. 57.g8N is the only winning move, and also a rare non-checking Knight-promotion. 79.c8N is not the only winning move, but in human terms: the best move."

He states that there are 5 double knight promotion games, but I have only ever found four on chessgames.com. Here is my list, in order of date.

MacDonnell-Bird, 1874

Zurakhov-Koblent, 1956

Schweber - Wexler, 1964

"This is the only game with two Knight promotions that were the strongest move. Promotions to Queen would have been equally strong, but as the Knight promotions were checks, they were more obvious, and therefore genuine." -Tim Krabbe

Kucuksari-Betanli, 2017

Can anyone find anymore games that feature two knight promotions?

Not all the games are by strong players, let alone, players, who are well-known, but here is a complete list in the Mega 2019 database. If you would like to see a particular game, or two, I can post the PGN, and add it to this answer.

This one is interesting since one of players is famous, and both promotions happened so early in the game.

 [Event "Greenhills op"]
 [Site "Greenhills"]
 [Date "1989.??.??"]
 [Round "?"]
 [White "Valdez, P."]
 [Black "Xu, Jun"]
 [Result "0-1"]
 [ECO "A25"]
 [BlackElo "2510"]
 [PlyCount "44"]
 [EventDate "1989.07.??"]
 [EventType "swiss"]
 [EventRounds "12"]
 [EventCountry "PHI"]
 [SourceTitle "EXT 2010"]
 [Source "ChessBase"]
 [SourceDate "2010.11.25"]
 [SourceVersion "1"]
 [SourceVersionDate "2010.11.25"]
 [SourceQuality "1"]
 [FEN ""]

 1. c4 e5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7 5. d3 d6 6. Rb1 f5 7. Bd2 Nf6 8. b4 O-O 9. b5 Ne7 10. Nf3 h6 11. O-O Be6 12. Qc1 Kh7 13. h3 Qc8 14. Kh2 Bf7 15. c5 g5 16. Qa3 g4 17. cxd6 gxf3 18. dxe7 fxg2 19. exf8=N+ Bxf8 20. Qa4 gxf1=N+ 21. Rxf1 Qd8 22. Qh4 Nd5 0-1

Here is a list of links to all of the games, minus the ones already in the question, from the list in order of date. Most of them are either the 365chess or chess-db databases. N/A is used for games that have not been found.

Kiili-Katajainen,1990

Valdez-Xu, 1989

Natri-Salokangas, 1990

Kosonen-Vuori, 1990

Dobos-Lehtivaar, 1990

Korhonen-Eskola, 1991

Lehto-Ketola, 1991

Carpenter-Scott, 1994

Myc-Walach, 1994

Sintici-Zubavicius, 1995

Norqvist-Kochetkov, 1995

Richards-Fongers, 1997

Rasmussen-Arnkilde, 1997-N/A

Doettling-Euler, 1999

Quintero-Bognar, 1999

Mellem=Borchgrevink, 2000

Reich-Lauer, 2002

Choma-Karstens, 2004

Urbisaglia-Del Cont Bernard, 2004

Vajcner-Vancat, 2006-N.A

Polok, Jagodzinski, 2006-N/A

Moura-Goncalves, 2006

Hager-Specht, 2007

KaunzingerSternheimer, 2008-N/A

Huszar-Gerendas, 2008-N/A

Kast-Becker, 2010-N/A

Khamko-Prosvetov, 2010

Hapke-Uksini, 2010

Bango-Bango, 2011-N/A

Simo-Volna, 2011-N/A

Woehl-Schwab, 2012-N/A

Effenberger-Barak, 2013

Bellahcene-Barbot, 2014

Lokwani-Lee, 2015

Radenic-Fikus, 2015

Fridman-Svane, 2015

Popchev-Dyulgerov, 2015

Davanso-Jenidarchiche, 2018


What is the best way to improve visualization? Visualization (seeing a chessboard, where the pieces are and how they can move moves ahead in your mind) is an important part of tactics and calculation.

What is the best way (or a good way) to improve it, I mean for beginners?

In my experience at first you should just work on chess as much as you can, especially on combinations. If you get comfortable with visualizing positions that result from the combinations you will notice to be able to also follow positions in chess books.
Then it's time to read endgame books. At first you will not be able to follow the moves too deep, but since the positions are simple you will be able to follow it for a while, that's useful for your endgame, and soon you will notice that it's getting easier to follow even deep lines.


Black answers to Grand Prix attack I am reading about the Grand Prix Attack and the main lines of development for Black. One line considered is as follows.
[FEN ""]

1. e4 c5 2. Nc3 d6 3. f4 g6 4. Nf3 Bg7 5. Bc4 Nc6 6. O-O

After White castling, I read, Black's best moves are Nf6 or Ne7 after e6.
As a beginner I want to ask, due to the fact that the idea behind the Grand Prix Attack is to attack Black's kingside, is queenside castling a line to consider for Black?

I play it to avoid 'normal' sicilian lines.
When possible I do attack often on the Kside.
OTOH your example line is not one that gives me a lot of problems.
What causes me more problems as white is fighting for an early d5 by black and attacking on the Q side.
Yes some opponents have castled Qside as black which led to other type of play than a Kside attack by white.


How do I identify strong pieces? Depending on the situation, some pieces that are ordinarily worth the about same value (say a knight and a bishop, or two of any piece) have different practical values because one piece is stronger than the other.

There's a few "strong" pieces I can think of that are a dream for an opponent to trade away.

A centralized knight
A fiancetto-ed bishop
A rook on the seventh rank

I've heard that sometimes it's in a players best interest to give up a rook for a strong bishop, just to give himself some breathing room.

How do I identify "strong pieces"?

How do I identify strong pieces?

Read books on pawn structures (Kmoch, Soltis, Baburin etc.)  Pieces are strong/weak entirely based on the landscape that gets carved out on the board through hostile negotiations that the purists call the Opening. Treacherous valleys, open plains and rocky crevices ... all of
these get created by different pawn structures. Know the structures
and you'll automatically see which pieces are going to become strong
and weak well before they get to that state.
Consider picking up some of the lighter and rudimentary books on strategy like Michael Stean's Simple Chess or Todd Barwick's Chess Strategy Workbook (which has a fantastic section description on what makes a piece strong or weak)

How do I produce (make my pieces strong, my opponent's pieces weak) in my own games?

Supplement your reading (see section above) with studying annotated Master Games to find these patterns and learn how the big boys execute on the typical plans associated with these sorts of strong-or-weak pieces. You'll slowly start to subconsciously (or consciously) emulate these ideas.
Review your slow time-control games with a stronger player to go over opportunities where you missed opportunities to strengthen or weaken a piece. After tactical safety is established, you should always be looking to improve your pieces (or diminish the usefulness of your opponent's pieces). Sometimes just doing this is more practical (with a clock running) than some fanciful deep strategic idea that is outside most mortal club player's wheelhouses (that the more advanced books notoriously confuse people with)


Equalize - What does it really mean? We often read or hear in books or video tutorials the following: "With this move, Black can equalize!". Some authors give 15-move or 20-move variations of some openings (e.g. Caro-Kann, Slav, Semi-Slav), then suddenly stop the explanation saying "...and Black managed to equalize".

Now, does "equalize" mean that Black should aim for "draw" at the start of the game? Should Black keep trying to "equalize" or "playing for draw" and wait for White to blunder then only star to think about how to win?

Does "equalize" mean that Black should try to exchange queens as early as possible?

Thanks!

This is a good question, because equality in chess is a tricky concept.

From a theoretical point of view there are only three evaluations of position: "White is winning", "black is winning" and "it's a draw". So, when we talk about white being better or black having a "slight pull", these evaluations are heuristics that mirror our experience of who is having the better practical chances and by what degree.

This also means that evaluations of the same position by different players can be quite different and often it is difficult to decide who is "more right".

So, when an author declares, that black has equalised, he means that he considers black's chances to not be worse any more. This doesn't say anything about the nature of the position. For example some GMs would argue that in the king's gambit, after 1.e4 e5 2.f4 ef black has already equalised. But obviously the position isn't drawish in the least, there is still a big fight ahead.

The idea that "trying to equalise first" is the same as "playing for a draw", comes from the fact, that it is often easiest to equalise by careful simplification. So there is a slightly artificial dichotomy between "trying to equalise first" and "going for a sharp fight". I call it slightly artificial because nowadays, especially among top players, the easiest way to equalise is often to go for the sharpest, most forcing lines.

As for what you should do: In my experience you should always try to develop counterplay, even if you are completely happy with a draw. If you can create even a slight initiative it is usually not difficult to exchange into a completely equal and drawish position. Whether exchanging queens should be your goal, depends entirely on the position.

In the end, how much risk you take is completely your decision. Some players try to go for the win straight away, even with black. Others want to play with the draw in hand, especially with white.


Do any grandmasters win more with black than white? Some statistics indicate white scores 52-56% - but I wonder if that differs according to playing style - e.g. perhaps strong defenders prefer the black pieces.
Do any former/current grandmasters have stronger win records with the black pieces than with white?
Note: the reason for choosing only grandmasters in this question is simply to ensure a large number of games had been recorded for the player so as to exclude any player who only played a small number of games

The short answer
Yes, they do, although very few GMs do and by a margin of less than 10%. This does not seem to be due only to random factors (see long answer).

An example is GM Joseph Gallagher. As you can see in his FIDE profile page, he has the following games record (as for 15 Dec. 2020):
White +124 =118 -73, score = 58.1%
Black +126 =124 -67, score = 59.3%

The long answer
To obtain the figure above I used the games published by TWIC, issues 920-1358 (25 Jun. 2012 to 16 Nov. 2020). I selected games where at least one of the players was a GM. And I kept only players with more than 50 games per color in the dataset. This ensures that scores are calculated with a 90% confidence interval of at least ±2%, and, since players in the dataset have in average a couple of hundred games, scores are usually still more accurate. The resulting dataset had 561K games for 1168 GM players.
In this case, the average scores where 65.5% for white and 56.9% for black. This is higher than in the databases you mention because being a GM most other players have a lower rating and they're more likely to win. (If I took only the games where both players were GMs, the average scores were 52.9% for white and 43.3% for black.)
As shown in the figure above, the average difference of scores between both colors is 8.6%, favorable to white. Still, there were 38 players who had better results overall with black. The five players with the highest difference in performance favorable to black in the dataset were:
                    WhiteScore  BlackScore  Difference
Bryan Smith            55.2        62.9        7.8
Essam El Gindy         52.0        58.8        6.9
Jean-Luc Chabanon      50.5        57.2        6.7
Justin Tan             54.5        61.2        6.7
Mihai Suba             57.9        63.8        5.9

I would like to bring your attention to one of these players, Mihai Suba, who is known for his book Dynamic Chess Strategy. In it he disagrees with white's first move advantage theory.
Note: If you look at these players' FIDE profile pages, you might find some discrepancies, due to the different characteristics of both datasets. The FIDE data includes all FIDE rated games (whether the player was already a GM or not); while my dataset contains games published on TWIC (FIDE rated or not) from 2012 to 2020 only if the player was already a GM.
But is it a correct answer?
Now, just because of randomness we would expect that some players had better results with black than with white. But is it the case? Do those players really perform better with black pieces or is it simply a random illusion? To check this I plotted the evolution of the score difference as the number of games increases for several players.

As you can see, the score difference varies widely when there are few games. But as the number of games increases, the variability decreases. In some cases, the score difference remains consistently above 0. In other cases, it occasionally crosses the line.
So, yes, there are some cases that cannot be considered a statistical artifact.
And what about differences in style?
You didn't really ask about it, but since you mentioned it in your question I had a look at it. For this I divided the players in three groups according to their score difference:

Upper 5%: Mostly players with better results with black
Lower 5%: Players with much better results with white
Those in the middle

And then I looked which kinds of openings they used, classified according to the five main ECO categories:

A: Flank openings
B: Semi-Open Games other than the French Defense
C: Open Games and the French Defense
D: Closed Games and Semi-Closed Games
E: Indian Defenses

It would seem that GMs who have better results with black pieces tend to use openings of the groups A and B more often than the other players, and the other groups less often. Although more detailed analyses would be necessary to arrive at more solid conclusions, this can give you some food for thought.

Update 19/02/2020
Dataset and script
Following the request by @stevec, I have shared the dataset and script used to write this answer on github.
It can be used to investigate some of the proposals made by other users (@HaukeReddmann, @SecretAgentMan) in the comments.
Further tests
@Grade'Eh'Bacon, suggested in a comment comparing the observed distribution of the difference in scores to the expected distribution under only random influences. I had already done this analysis, but I decided not to include it because the answer was rather long. But since it has been requested, I share it here.
If the distribution shown in the score differences plot at the top of the answer was due only to random factors, we would expect a normal distribution (aka Gaussian distribution, bell curve). This is the hypothesis assumed in Elo calculations and can be checked with a Monte Carlo simulation.
One way to test if a variable follows a normal distribution is with a Q-Q plot (see below). If the observed score difference followed a normal distribution, the points would be close to the diagonal line. This happens in the middle zone, but not in the extremes. We have a distribution with heavy tails, that is, there are too many players with better results with black and too many players with much better results with white to be due to random causes alone.

The results of the Shapiro-Wilks test, which is also used to test for normality is also consistent with the hypothesis that the distribution is not normal. This supports the hypothesis that there is something else going on apart from randomness.
And I also repeated the analysis with another independent dataset of games from the ICCF. And I obtained comparable results.


Are there any vegetarian or vegan Masters apart from Anand? Are there any other vegetarian or vegan chess GM players, apart from Vishy Anand?

A quick Google search turns up the following two:

Jonathan Speelman. Three time British champion and at one point #4 on ELO rating list.

Peter Leko. Almost World Champion at one point.

Sources:

http://www.unleashed.org.au/who_cares/vegetarian_athletes.php?athlete=jonathan-speelman

http://www.veganwolf.com/famous_vegetarians.htm

http://www.veggieboards.com/forum/11-vegetarian-support-forum/72707-chess-world-champion-vegetarian.html

http://chess.jliptrap.us/grandmasterdiet.htm


Is this a chess variant? Chess without taking pieces! I just noticed a special style of playing chess in some of the top games in chess.com; A chess without taking pieces:

The whole game here:

[FEN ""]
[Event "Live Chess"]
[Site "Chess.com"]
[Date "2015.07.09"]
[White "adypady02"]
[Black "Thunder_Penguin"]
[Result "1/2-1/2"]
[WhiteElo "2240"]
[BlackElo "2019"]
[TimeControl "3|0"]
[Termination "Game drawn by agreement"]

1.e4 Nf6 2.Nh3 Nc6 3.Nf4 Nh5 4.Ne6 g5 5.Ba6 Nf4 6.Qe2 Ne5 7.f3 Nh3 8.g4 Ng6 9.d4 Bg7 10.Bf4 f5
 11.Qf2 Nh4 12.Nc3 Kf7 13.Nd5 Bf6 14.Rd1 Re8 15.Rd2 Kg8 16.Kd1 Kh8 17.Kc1 b5 18.Kb1 Bb7 19.Ka1 Kg8 20.Bd6 Kf7
 21.c4 Rg8 22.c5 Qf8 23.c6 Qh6 24.a4 Raf8 25.a5 Ke8 26.b4 Rf7 27.Kb2 1/2-1/2

Is this a chess variant?
What is its name?
Is it quite well known?
What's the objective of the game, still checkmating?
Any hints for a winning strategy?

Another games :

game 2
game 3

I followed the profile of Thunder_Penguin in chess.com and found a blog post about this: some  variation.

Ady and I made this.
Rules:
To win, get your king to your two corners (a1 and h1 for White,
h8 and a8 for Black)

You can't capture pieces*
You can't put pieces on the last rank (1st or 8th)
You can't castle*
You can capture if it's mate in 1
You can't control the enemy squares (ie, white can't put a knight on b6)

Let the analysis begin!

So according to this, answers to questions would be:

Is this a chess variant? What is its name? Is it quite well known?

It's a recent attempt to create a variation , made up by the 2 players. not named, not known.

What's the objective of the game, still checkmating?

The objective is not checkmating but escorting the king to one of your side corners following the rules cited.

Any hints for a winning strategy?

I can't answer that.


Have any top players intentionally thrown a game for tournament reasons? I'm thinking something similar to Women's Badminton at the 2012 Olympics. There, some pairs actively attempted to lose their games to gain a more favorable draw in the next round.

Has anything like this happened in chess? I'm aware of the Candidates tournaments of the past where Soviet players allegedly played quick draws against each other to conserve energy against Fischer, but I'm not aware of intentional losing.

As an example of what would qualify, suppose in some 20-player tournament, the top 6 qualify for the next stage (this has happened in Candidates tournaments in the past). In the penultimate round, the runaway leader Alice has more or less qualified, but the 6th and final qualification slot is still up for grabs, with three players Bob, Charlie and Denise in contention. Alice is scheduled to play Bob in the round. She thinks Denise is the most threatening opponent, so it's in her best interests to lose to Bob and give Bob some help in qualification.

I'm not interested in match fixing to, e.g., make money in the betting markets; I'm only interested in losing for personal gain because of the crosstable & tournament format. I'm also not interested in draws - only intentional losses.

Yes.
But not very many incidents.

In the old days,it was thought that some Russians were forced to throw games at times to help other players that were thought more likely to win the tournament so as to beat other countries' players.


Worst grandmaster by rating https://www.chess.com/forum/view/fun-with-chess/worlds-lowest-rated-grandmaster
This is a joke thread about the 'world's worst grandmaster', Panko Smoobachuk. Seeing this post, I wondered, what is the world's lowest rated grandmaster?

The new, munged* FIDE rating website still has the old "Advanced Search" option, but the page doesn't have its own URL. There you can search for GMs from all countries sorted by rating ascending and then you get that the Russian GM, Vasily B Malinin, born in 1956 is the lowest rated GM with a standard rating of 2100.
Looking at his individual calculations shows that his rating has been in steady decline since 2004 which would suggest some life-changing event happened then, perhaps a health problem, which affected his chess playing ability.
*mung = self referential acronym = Mung Until No Good


I refused to sign the scoresheet but the arbiter signed with my initials. What should I do? I refused to sign my scoresheet, as I was planning to lodge an appeal. Yet, the arbiter signed the scoresheet with my initials. I know I didn't lose my right to object. However, I'm afraid that my appeal will be denied because the claim that I didn't sign the scoresheet will be disputed.
What should I do and how can I prove otherwise?

If the arbiter really signed with your signature, instead of his, then he just committed a crime (forgery of documents). He could have signed with his signature as proof that he confirmed the result of the game and everything on the scoresheet.
If the arbiter really forged your signature, then as a first step you should lodge a complaint against the arbiter with the tournament organizer. Next, if necessary, do the same with the federation that organizes the tournament. Depending on how serious the matters are, the police may be involved, but most likely you can solve it peacefully.
Obviously in parallel, you still put your initial claim about the game on appeals committee desk.


How much worse do GMs play in their blitz and bullet games? How much of a skill drop is there when a GM plays a blitz game or a bullet game versus rapid and classical?

What I mean is, imagine if Carlsen was given 1 minute to play in, and he played against somebody who was given 1 hour to play in. What must the rating of this opponent be in order for them to be equally matched? In other words, what is the "classical rating"-equivalent of Carlsen's bullet-rating? And the same for blitz?

Obviously you cannot answer this by actually playing Carlsen against somebody who can think for longer, because Carlsen would also be able to think while his opponent is taking their time and that's not what I'm looking for.

But I suspect by analyzing the quality of the games that Carlsen plays, one could compare them to his classical games and perhaps estimate what "classical-rating" skill-level he is playing at when he plays blitz?

Handicapping

I've played in blitz tournaments where the higher rated player was handicapped 1 minute per 100 rating points with a maximum of 3 minutes deducted.

When you play with one 1 minute physical ability becomes a huge factor.  If you are not fast enough to move a piece while your opponent is reaching for his clock, and then hit your clock near immediately after your opponent, you will likely lose on time.

There is an endurance factor as well.   When you play blitz or bullet it is typically a lot of games in succession.  You might note that in the recent Côte d’Ivoire Rapid & Blitz (which Magnus dominated), the quality of the blitz games dropped significantly as the day went on -- this is typical of these type of tournaments and you often see players brains just stop performing.

  Overall Strength

We don't have data on GM's playing with huge time handicaps as you proposed, but we can see their quicker games and compare them to their slower games.  Of course they have multiple FIDE ratings to represent this.  Magnus is further ahead of the world in rapid than he is in classical.

I personally think that when the players are young and in great form, they don't need much time.   When Anand was a rising star he played classical games at blitz speed.  Kamsky too played fairly quickly.  This is strategic as older GMs need to take their time and would get into time pressure.

Probably a computer program could rate the quality of the games to get a non-opinion based answer to your question.  My personal opinion is that if classical was level 10, rapid would be 7-8, blitz 5-6, and bullet under a 4.

Then it would be interesting to compare these against IM or Master games.  My guess is that GM games at Rapid are still better than IM classical games.


Is there an online PGN editor for Blank Chess? Blank Chess is a variant where the board starts empty and the first two moves are placing the Kings on your side of the board. You can then either place a piece or move a piece in subsequent turns.

I recorded a game I played with my son in the same notation one would use for CrazyHouse, and would like to record it in a PGN (or BPGN) format to show it to friends.

Does anyone know where I can find such an editor online, or failing that, one that I can download to my Mac?

Caissa's PGN Editor claims to be what you want.


Why was this game drawn on lichess? https://lichess.org/qgvWa0ly

I (black) was losing and ready to resign soon. As far as I can tell, there should be no stalemate or 50 move rule applicable. I had offered a draw earlier, but it was declined. Can the opponent accept the draw later after first declining? That wouldn't be fair.

In a chess there's a 3-fold repetition rule, if the same position appears 3 times, a player can call a draw. Your opponent allowed a 3-fold repetition, hence, the game was drawn.

3k4/8/p1PK2p1/1p4P1/1P6/P7/8/8 w - - 11 57

Edit: clarifying in light of comments:

Note that the draw does not happen until claimed by a player, and since you didn't claim it, your opponent must have. Why would they claim a draw in a winning position where they had more time on their clock? On lichess.org, you can control the "claim draw on threefold repetition automatically" setting. Yours is set to "when time remaining <30 seconds", but the opponent's must have been set to "Always". Players who normally play under faster time controls sometimes use the "Always" setting to ensure predictable draws under time pressure. You got lucky in this situation because your opponent didn't recognize the 3-fold repetition, and their winning chances were undone by their settings.


How did you come up with this line?

Castling kingside on move 13 right into the attack, looks like suicide for black to me.

Also I don't see the point of white sacrificing the queen. Instead of giving black the dream square on e5, I'd first play h4 and only then g5, so that you can recapture on g5 with the h pawn.

Regarding your position at the end of your variation, it is probably just equal. Black does not have any particular weaknesses and also there does not seem to be any immediate threat of an attack on the black king anymore. Compare this with the queen sacrifice Caruana played in the game where he had only 2 pieces for the queen, but complete dominance on the light squares.


Is there any software or web service for club-level Elo ratings? Is there any software (or web-based service) that allows you to keep track of local, club-level Elo ratings?

These ratings would not have any connection with official Elo ratings, it would be just an Elo rating within the universe of players in a club (i.e. games in various social tournaments would compute for the rating).

Even if it is not available, something like this is not too hard to implement yourself. Here is an example with extremely silly and simple rating system that is just meant to give you an idea. But I don't think that using actual Elo formula that much harder.

EDIT: I edit my implementation to use Elo formula (not including floors) given by the formula here

def get_exp_score_a(rating_a, rating_b):
    return 1.0 /(1 + 10**((rating_b - rating_a)/400.0))

def rating_adj(rating, exp_score, score, k=32):
    return rating + k * (score - exp_score)

class ChessPlayer(object):
    def __init__(self, name, rating):
        self.rating = rating
        self.name = name
    def match(self, other, result):

        exp_score_a = get_exp_score_a(self.rating, other.rating)

        if result == self.name:
            self.rating = rating_adj(self.rating, exp_score_a, 1)
            other.rating = rating_adj(other.rating, 1 - exp_score_a, 0)
        elif result == other.name:
            self.rating = rating_adj(self.rating, exp_score_a, 0)
            other.rating = rating_adj(other.rating, 1 - exp_score_a, 1)
        elif result == 'Draw':
            self.rating = rating_adj(self.rating, exp_score_a, 0.5)
            other.rating = rating_adj(other.rating, 1 - exp_score_a, 0.5)

This works as follows:

>>> bob = ChessPlayer('Bob', 1600)
>>> john = ChessPlayer('John', 1900)
>>> bob.rating
1600
>>> john.rating
1900
>>> bob.match(john, 'Bob')
>>> bob.rating
1627.1686541692377
>>> john.rating
1872.8313458307623
>>> mark = ChessPlayer('Mark', 2100)
>>> mark.match(bob, 'Draw')
>>> mark.rating
2085.974306956907
>>> bob.rating
1641.1943472123305

Here is my original python implementation:

class ChessPlayer(object):
    def __init__(self, name, rating):
        self.rating = rating
        self.name = name
    def match(self, other, result):
        if result == self.name:
            self.rating += 10
            other.rating -= 10
        elif result == other.name:
            self.rating += 10
            other.rating -= 10
        elif result == 'Draw':
            pass

This works as follows:

>>> bob = ChessPlayer('Bob', 1600)
>>> john = ChessPlayer('John', 1900)
>>> bob.match(john, 'Bob')
>>> bob.rating
1610
>>> john.rating
1890
>>> mark = ChessPlayer('Mark', 2100)
>>> mark.match(bob, 'Mark')
>>> mark.rating
2110
>>> bob.rating
1600
>>> mark.match(john, 'Draw')
>>> mark.rating
2110
>>> john.rating
1890


How does a chess engine mimic an Elo rating I am a fairly new chess player (say 1400) and I would like to play against Stockfish and win some of the time. If I change the strength to 1400 then what does the algorithm actually do ? Does it make random blunders or does it simply reduce its depth and thereby only see the easiest tactical combinations of moves. If so, what would the depth be for a 1400 rating ?

In strength reduction mode, Stockfish starts a multi-pv where the engine searches for more than one best move. When the engine needs to make a move, it looks for all the possibilities in the multi-pv moves and choose a move with the following algorithm:

Filter out a move if it's a gross blunder. It does that by comparing its score with another multi-pv score.
Generate a small random number and applied it to a multi-pv score
Pick the move if the transformed score is the best

It might sound complicated but it isn't, let's do an example.

Say, I exchanged my queen with yours. You could take my queen with your bishop or pawn. If you did it with your bishop, the position would have been equal. If you did with your pawn, your pawn position would have been ruined and lead to a slightly inferior position. If you did anything else, I would be a queen ahead.

A possible scoring would be:

BxQ -> 0.00
PxQ -> -0.34
Kh8 -> -9.99

Not taking back the queen is a gross blunder and should be avoided whenever possible. When applied to the algorithm:

Calculation

Engine considers BxQ

The best score is 0.00. Since this is the first move, there is nothing to do.

Engine considers PxQ

Notice that without giving the move PxQ a small random boost, it'd never would be chosen because the best score (0.00) is greater than the score for PxQ (-0.34).

Stockfish generates a small positive number and add it to PxQ. Now, there're two possibilities. If the random number is too small, say, 0.10, the added score (-0.34 + 0.10 = -0.24) is still too small compared to the best score (0.00), and it'd been discarded. If the generated random number is sufficient to push the PxQ score above the best score, for instance, 0.40. The new score for PxQ would have been 0.06 and it's greater than 0.00. Therefore, Stockfish would pick the PxQ.

Engine considers Kh8

Not taking back the queen is a gross blunder. The difference between it with the previous move is too big (-9.99 - -0.34). Stockfish wouldn't consider it, and discard it immediately.

Implication

The engine will not play random chess
The possibility of making an inferior move depends on the random generator. The generator usefulness also depends on the strength level. The weaker you ask Stockfish be, the more likely the generator will generate a bigger number.
Stupid blunders are avoided
The move Stockfish plays is unpredictable, simulating human's unpredictable behavior.
Stockfish doesn't mimic Elo rating. It only gives you 20 strength levels.

Edited

The poster was concern about a link to the Stockfish for iOS in the comments. Please note that the statement in the link "Set the strength of the engine on a 0 to 2500 scale. This scale roughly corresponds with the human ELO scale. 0 is absolutely terrible play, while 2500 is maximum strength." is misleading and simply wrong. To see why, the page wasn't written by a Stockfish engine developer. The writer misinterpreted the scaling reported in the app. In reality, if you give the app, say Elo 2000, the app maps it to one of the 20 strength levels. Whatever Elo rating that you see in the app means absolutely nothing, it's just an easy way for an end-user to adjust the levels. There is no direct relationship between a strength level to a Elo rating. Think like this, if I modify the source code and expand the range from 0,20 to 0,40. Now when you choose strength 30, what's the rating? I could tell you it's Elo 2400, or Elo 2500, or Elo 3500.

At the end of the day, Stockfish doesn't mimic Elo strength. The Elo labels that you see in the app are simply just beautiful labels that pretend there is a relationship.


Searching for players by primary opening choice My opening repertoire consists mostly of openings that score respectably at the club level but rarely appear in high-level play, and far more rarely as any high-level player's primary choice rather than a secondary or tertiary surprise weapon.  I'm interested in studying games played by strong (preferably 2500+ FIDE) players who genuinely believe in the theoretical strength of these openings, fervently enough to play them as primary weapons, willingly walking into their opponents' preparation rather than relying on surprise.  For example, players as strong as Magnus Carlsen have pulled out the Dutch Defense on rare occasions, but I'm more interested in players like GM Vladimir Malaniuk, who played the Leningrad Dutch against 1. d4 about three times as often as everything else put together and even managed to hold a draw against Kasparov with it, and GM Simon Williams, whose primary weapon against 1. d4 is the Classical Dutch.  Similarly, many GMs trot out the Dragon Sicilian with varying rarity as a secondary weapon after the Najdorf or the Sveshnikov, but I'm only interested in players like GM Gawain Jones who statistically prefer it over all alternatives and play it regularly against the likes of Carlsen.
What's the best way to go about this search?  I can search for whoever has the most games on record in a given line, but I've found that that often just leads me to players with an exceptional quantity of games on record in general.  I can search for the highest-rated games in a given line, but that just turns up superGMs playing that line for the first time in about six months as a shock tactic.  I can Google "grandmasters who play the Whatever", but surprisingly that too leads to players who only occasionally use that opening.  I can't even go by authorship of opening books; it's entirely too common for a GM to write an intro gushing about how the Such-and-Such has been their dearest and most reliable ally in 30 years of tournament play, but for the database to show that they tried it out for (at most) a scant dozen games and then promptly went back to the standard Berlin/Nimzo repertoire.  And of course, Kasparov played nearly everything at one point or another and contributed importantly to the theory, so that's a frequent confounding factor in any search (notice how often devotees of any given opening will boast that Kasparov himself played it, quietly implying that it was his main weapon).  Is there a better way to specifically look for players who prefer a given opening line and play it more frequently than the alternatives?
As a wonderful bonus, it would also be great if there's some way to filter for recency.  Carlsen for example has a surprising proportion of Dragon games on record for a superGM, but apparently hasn't played it since 2014, so even if he may have believed in it before, he clearly hasn't for some time.

The opening explorer at 365chess dot com shows which player played the position at hand most often, while also showing most recent examples.


What's the best way to get the top n engine moves? I want to use python-chess to get the top 5 Stockfish moves from a given position with a numerical evaluation for each move. Is it more accurate to run the engine for 10 minutes with MultiPV=5, or to quickly rank all the legal moves (with maybe 1-2 seconds engine time each) and then let the engine think about the top 5 or so one at a time for 2 minutes?

Both approaches will work.

In the second approach, you will have better accuracy of your evaluations but you may miss an important move. For example, if 20...Rxc3 positional exchange sacrifice is a strong move, you will probably miss it with a 1-2s quick engine search.
In the first approach, you will lose accuracy but you won't miss a strong hidden resource like in the second approach.

Classical example of sensitivity vs false positives. The second approach is more sensitive but you trade it with higher false positive rate.
In Chessable engine analysis, I adopted the second approach. I gave about 10s for each legal move (there could be many!). Filter out only the top moves, then seek evaluation for each individual move. 1-2s is too little.
PS: MultiPV is causing lose in accuracy because the engine has to evaluate the moves before those moves are played on the board.


Is there a good program to play chess online in ubuntu? I really missed playing chess with someone who know how to play, I am looking for a good program to play chess online from ubuntu computer.
Any Ideas?

On ubuntu, you can download Firefox, Chrome, or any other browser of your choice. From within that browser, go to lichess.org, chess.com, or chess24.com, create a free account, and play against others online.


Legality of swapping identical pieces In an offhand blitz game without touch-move, my opponent, on his opening move as White, just to be a wise guy, picked up his b1 knight and put it down on f3, then moved his g1 knight to b1, and punched the clock. He did it all with one hand. Apart from rules against distracting or annoying ones opponent, did he make a legal move?

In an offhand blitz game without touch-move

In other words, you are not playing by the official rules of any chess federation, either national or international. You are playing by your own rules. So, you and your opponent, as the arbiters of the rules you are playing by, are the ones to decide whether or not what was done was legal.


What is the problem with my negamax implementation? I am currently attempting to make a basic chess engine in Python (Learning some basic concepts), but for some reason the engine is suicidal and does not detect the scholars mate. I am using python-chess for the board because I am lazy, but I think the issue is my implementation of negamax? I've read on chessprogramming wiki but still can't figure out the issue.

Here is the code on GitHub: https://github.com/AggressiveBee15/LousyEngine

I didn't run your code, but by just looking:

You should return the score when score >= beta. This is consistent to Wikipedia:

Note when alpha >= beta, Wikipedia returns the score, not beta.

Your code doesn't detect checkmate? I don't see how your engine can report Scholar mate without detecting checkmate.
Minor issue. The condition should be >= not >, but that shouldn't change anything.
What outputs did you get from: print('New good move ...?


Two Rooks vs Queen endgame Is an endgame with Queen and King vs. two Rooks and King a win for the Queen, a win for the two Rooks, or a draw?

Generally speaking, it's a draw. Most pawnless endgames are drawn, unless one side has a material advantage of more than a minor piece. Either side can win if there are short-term tactics. To check the outcome of a position, you can use an online tablebase. In particular, it's nice to view the longest wins for either side, which are (according to this page) are
[FEN "k2q4/7R/8/8/8/8/8/2K3R1 w - - 0 1"]

(White to move, mate in 29)
and
[FEN "4r3/8/5Q2/8/5r2/1k6/8/1K6 w - - 0 1"]

(White to move, mate in 49)


How big is the "opening book" of a typical tournament player How many openings does a typical (national/international level) tournament player usually know and play?

For instance: in a tournament, can I expect that a player will either open 1.d4 or 1.e4 consistently when they have white? And, if black plays (for instance) 1...e6, can I expect their move 2 to be always the same? How long of an opening line will they typically follow without changes (given the opportunity)?

Or maybe they have a single opening that they play 80% of the time, for instance, and then they change completely when they feel like doing something different?

I am not speaking about top-level matches such as a world champion match, where many matches between the same two players are played with a lot of preparation, and I can expect them to vary a bit more.

It depends.

Myself I play at a 1900 FIDE level and I have practically never studied openings!

Take as an example two players of my club rated 2250 FIDE:

Player A: theory enthusiastic: This player not only have a repertory close to an IM, but he went to a pub before each game to
study possible development of the games taking in consider what
openings his rival played.
Player B: tactics enthusiastic: This player do not study more theory and just played for fun at the club. He of course know some
basis because to reach that level you need to survive against every
+2000 the first ten moves, but he never prepared any game and uses to fall in second non book lines at the first moves.

Anyhow at a titled level everybody has a repertory. But also at this level there are some masters that know very deep lines of a huge repertory: more than fifty openings with more than ten lines on each one, to make a rude calculation, and others that just do not fall in ambushes, but as player B of my club can fall in non book lines to make think their opponents.


Python script to let stockfish selfplay 10 games from a given position I would like to have Stockfish to selfplay 10 games starting from a given position. Game should end after 10 moves. From the python-chess documentation there is an example of playing only one such game, starting from the initial position. Thanks in advance.

import chess
import chess.engine

engine = chess.engine.SimpleEngine.popen_uci("/usr/bin/stockfish")

board = chess.Board()
while not board.is_game_over():
    result = engine.play(board, chess.engine.Limit(time=0.1))
    board.push(result.move)

engine.quit()

This should get you started, up to you to add extra features based on your objective (such as saving the games and moves, etc.)

import chess
import chess.engine
import os
import sys

arguments = sys.argv
pondertime = float(arguments[1]) #first argument: ponder time in sec
maxmoves = int(arguments[2]) #2nd argument: max number of desired moves
gamecount = int(arguments[3]) #3rd argument: max number of games to play
#here we assume the engine file is in same folder as our python script
path = os.getcwd()
#Now make sure you give the correct location for your stockfish engine file
#...in the line that follows by correctly defining path
engine = chess.engine.SimpleEngine.popen_uci(path+'/'+'stockfish-10-64')

dictsidetomove = {True:'white',False:'black'}
notationdict = {True:'.', False:'...'}

for i in range(gamecount):
    board = chess.Board() #give whatever starting position here
    while not board.is_game_over() and board.fullmove_number<=maxmoves:
        result = engine.play(board,chess.engine.Limit(time=pondertime))
        print(dictsidetomove[board.turn]+' played '+str(board.fullmove_number)+notationdict[board.turn]+str(board.san(result.move)))
        board.push(result.move)
    print('Iteration '+str(i+1)+'-----')
    print(board)
    print('Final position FEN: ',board.fen())
    print('-----')

engine.quit()

Here's an example running it for engine time of 0.1 sec, 10 move game, and 1 game to be played only:

python selfplay.py 0.1 10 1

Printed output:

white played 1.e4
black played 1...d5
white played 2.exd5
black played 2...Qxd5
white played 3.Nf3
black played 3...Nf6
white played 4.Nc3
black played 4...Qd6
white played 5.d4
black played 5...a6
white played 6.Bd3
black played 6...Nc6
white played 7.O-O
black played 7...Bg4
white played 8.Ne4
black played 8...Nxe4
white played 9.Bxe4
black played 9...O-O-O
white played 10.Be3
black played 10...g6
Iteration 1-----
. . k r . b . r
. p p . p p . p
p . n q . . p .
. . . . . . . .
. . . P B . b .
. . . . B N . .
P P P . . P P P
R . . Q . R K .
Final position FEN:  2kr1b1r/1pp1pp1p/p1nq2p1/8/3PB1b1/4BN2/PPP2PPP/R2Q1RK1 w - - 0 11
-----


Is a Caro-Kann game still advisable after 1. e4 c6 2. g4? For the record, I have already made my move. I am black and I moved 2. ... d5. But I am wondering if that was a mistake. I am a total newb and am trying to learn the Caro-Kann. As I understand it, after 1. e4 c6, black should play d5 regardless of white's response. However, I have not found any analysis on 2. g4.  Was my decision to go 2. ... d5 a mistake?  Is this still a Caro-Kann game or is it something else now?

Thanks!

The g4  line is called the Spike Variation of the Caro-Kannn(B10). Commonly played line is 2...d5 with e5 there after. White gives up development of pieces for more spatial control.


Relative value of chess pieces on queenside vs kingside I've read a few variations on the relative value of chess pieces ( Q=9, R=5, N=3, B=3, P=1 ), but I've yet to encounter a variation in value according to the side of the board the piece is on. With regard to rooks, bishops and knights, might there be a a different inherent value whether on kingside or queenside? For instance, I've always found a greater value to kingside bishops because of their inherent nature of attacking the opposing king's squares before and after castling.

Has anyone seen any documented systems based on this idea? I'm not looking for speculation.

I don't think that there's any value to where the pieces start, but the value of the pieces changes drastically depending on where they are on the board at a given time.

For example, a white knight on d6 that can't be exchanged off is usually considered to be worth a rook.  Similarly, if black has castled kingside with pawns on f7, g6, and h7, and white has an unopposed dark square bishop, that bishop can be worth a rook (at least) if white can attack the black king.

The only pieces that are inherently different are the bishops (one light, one dark), but they're still equal until the pawn structure has been determined.  A bishop is usually strong when the opponent's pawns are on its color (so they can be attacked) and the friendly pawns are on the opposite color (so they don't get in the way).


Stalemate situation with all pieces on the board Suppose all the pieces are on the board. Does there exist a position such that

A) one of the players can't make any move (a stalemate)?

B) neither player can make any move (a double stalemate)?

Here is an example of a 12-move game after which White (to move) is stalemated. All 32 units (pieces and pawns) are still on the board. The original version of this concept game was created by Charles Henry Wheeler, and published in Sunny South in 1887, according to Edward Winter's C.N. 3679. Samuel Loyd is often, and wrongly, given credit.

[Title ""]
[StartFlipped "0"]
[fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

1.d4 e5 2.Qd2 e4 3.Qf4 f5 4.h3 Bb4+ 5.Nd2 d6 6.Qh2 Be6 7.a4 Qh4 8.Ra3 c5 9.Rg3 f4 10.f3 Bb3 11.d5 Ba5 12.c4 e3 1/2-1/2


Least number of moves to achieve a complete switchover of nonpawns in starting setup [fen "RNBQKBNR/8/8/pppppppp/PPPPPPPP/8/8/rnbqkbnr w - - 0 1"]

During a comp, my friend an I had a team kill and we decided to make this position(legally) before drawing. Then we continued to find more and more optimal ways of getting the position until I found this:

[FEN ""]

1. a4 a5 2. Ra3 Ra6 3. Rb3 Rc6 4. Rb6 Rc3 5. Ra6 Ra3 6. Ra8 Ra1 7. h4 h5 8. Rh3 Rh6 9. Rg3 Rf6 10. Rg6 Rf3 11. Rh6 Rh3 12. Rh8 Rh1 13. e3 e6 14. Qg4 Ke7 15. Ke2 Kd6 16. Kf3 Qf6+ 17. Ke4 Kc5 18. d3 Kb4 19. c3+ Kb3 20. Qg5 Kc2 21. Na3+ Kd1 22. Nh3 Qf3+ 23. Kd4 Ke1 24. Qd8 Qd1 25. Ke5 Nh6 26. Ng5 g6 27. Kf6 Bg7+ 28. Ke7 Nc6+ 29. Ke8 Nd4 30. c4 Nf3 31. b3 b6 32. Nb5 Ng1 33. Ba3 Bb2 34. Bf8 Bc1 35. g3 Bb7 36. Bh3 d6 37. Nh7 e5 38. Bc8 Bg2 39. Nf6 Bf1 40. Ng8 Nf5 41. Na7 Nd4 42. Nc6 Ndf3 43. Nb8 Nd2 44. b4 Nb1 45. d4 d5 46. e4 c5 47. f3 b5 48. f4 f5 49. g4 g5

Is there any faster way of achieving this position? And (as an extra question) does anyone have a position that have the longest legal optimal series of moves to achieve it?

As @chakerian's calculations show, 40 moves is the minimum. After a bit of puzzling, I found the solution.
[FEN ""]

1. a4 {First, we need to get the rooks in position. They'll be hard to swap once the board is full.} a5 2. h4 h5 3. Rh3 Rh6 4. Rg3 Rf6 5. Rg6 Rf3 6. Rh6 Rh3 7. Ra3 Ra6 8. Rc3 Rb6 9. Rcc6 Rbb3 10. Ra6 Ra3 {Now, we can start with the knights. They're tricky because they need to swap places via the four center squares. Note that we cannot move the center pawns *before* the knights.} 11. Nf3 Nc6 12. Ne5 Nd4 13. Nc6 Nf6 14. Nc3 Nd5 15. Ne4 Nc3 {It's time for the kings to come out of their hiding, but they have do this carefully because of the knights.} 16. Rh8 d5 17. Ra8 Kd7 18. Nf6+ Kd6 19. e4 Ra1 20. Ba6 b5 21. Nb8 Kc5 {The black monarch chooses queenside - that means his colleague has to take the other one.} 22. Ng8 Nde2 23. d4+ Kc4 24. Kd2 Rh1 25. Ke3 Ng1 26. Kf4 Bh3 27. g4 f5 28. Kg5 e5+ 29. Kg6 Bf1 30. Bh6 {Note how the c1-h6 and a3-f8 diagonals have been left open for the transfer of the last four pieces.} Qg5+ 31. Kf7 Ba3 32. Ke8 Qc1 33. Qd2 Nb1 34. Qg5 {OK, we're almost there now, from here it's a walk in the park.} Qd1 35. b4 Kc3 36. Qd8 g5 37. Bf8 c5 38. Bc8 Kd2 39. c4 Bc1 40. f4 Ke1 {And we're done!}

To answer the second question: you're looking for the longest unique proof game. I found the longest known one here and here.
[Title "Dmitri W. Pronkin & Andriy Frolkin, Die Schwalbe 06/1989, 1st Prize, PG in 57.5"]
[FEN ""]

1. a4 h5 2. a5 h4 3. a6 h3 4. axb7 hxg2 5. h4 d5 6. h5 d4 7. h6 d3 8. h7 dxc2 9. d4 a5 10. Bh6 c1=R 11. e4 Rc5 12. Ne2 Rh5 13. e5 c5 14. e6 Nc6 15. b8=R a4 16. Rb4 a3 17. Ra4 c4 18. b4 c3 19. b5 c2 20. b6 c1=R 21. b7 Rc4 22. b8=R Qa5+ 23. Rbb4 Bb7 24. N1c3 O-O-O 25. exf7 e5 26. Rc1 Bc5 27. f8=R a2 28. Rf3 a1=R 29. Na2 g1=R 30. Rfa3 Rg6 31. f4 Re6 32. f5 g5 33. f6 g4 34. f7 g3 35. f8=R g2 36. Rf5 g1=R 37. Bf8 Rg7 38. Ng3 e4 39. Bd3 e3 40. O-O e2 41. Rcc3 e1=R 42. Bc2 R1e3 43. d5 Rdd7 44. d6 Rdf7 45. d7+ Kb8 46. Qd6+ Ka8 47. Qc7 Nge7 48. d8=R+ Nc8 49. Rdd3 Rhg8 50. h8=R Rae1 51. Rh6 R1e2 52. R1f2 Rce4 53. Kf1 Bd4 54. Rfc5 Ne5 55. Nf5 Nc4 56. Nd6 Nb2 57. Rbc4 Nb6 58. Qb8+

What this really means, is that the final position can be reached in 57.5 moves (not less), and that there is only one way to do this. In your example, moves 48 and 49 (and many others) could be switched. Also, currently there is no other position with this characteristic known which takes more moves to obtain.


What is the best defense against the King's Indian Attack? How can I break the King's Indian Attack? I think my h7 square is vulnerable to attack; what is the best way to break this strategy?

I doubt that the King's Indian Attack can be 'broken'.  It's a very solid position that White takes the time to setup, if Black is not careful, White may be able to gain space on the kingside, with moves such as e5, and develop dangerous attacks if Black has castled there.

As for h7 being weak, many things need to happen from Black in order for this to be realized (such as a semi-open h-file, Bg7 has been exchanged, in which case it is h6 that is weaker), so there may not be anything there worth exploring.

I can't comment on what the 'best' defense would be, but there are many good ones, one such is the Botvinnik System.  Black makes use of the extra available tempi to set up a strong and flexible defense.  The typical structure would be pawns at c5, e5, d6, g6 and pieces at Nc6, Nge7, Bg7 and 0-0.  Black has a firm control over the d4 square and can potentially break with either ...b5 or ...f5.


Chess Clock as Birthday Gift Advice My boyfriend has an old beige/white Chronos II that needs repair. I've decided that perhaps purchasing a new clock for his birthday would be a better idea than my original idea (a chess coffee table book...really for me to improve the apartment decor!). But now after looking around I see it is very hard to acquire the Touch Chronos II. Can anyone recommend a suitable replacement? Hopefully one that complies with FIDE regulations and has tactile buttons.

Section 5.5 of the FIDE handbook lists the following approved clocks:

5.5. The electronic chess clocks endorsed by the FIDE
5.5.1. DGT XL (year 2007)
5.5.2. DGT 2010 (year 2010)
5.5.3. Silver Timer (year 2007)
5.5.4. Sistemco (year 2009)
5.5.5. DGT 3000 (year 2014)
5.5.6. CE Clock (year 2017)
5.5.7. KK9908 Clock (year 2017)


How can I convert screenshot capture into FEN to analyse on Windows 10+? I want to analyze position presented on meeting, web page or video but problem is that I have not FEN to start such analysis. It need manual work to do it.
I want to capture screenshot than convert it into FEN. How can I do it on Windows 10+? (not create image/scan than process it with external tools which is not doing screenshots - I know how to do it in such way.)
On Windows I can use Shift+Window+S to capture region than save to image or to clipboard. Is anybody using some software or tool to do it?
I can write such software with use deep learning but it takes time and maybe it is not need to invent wheel again.

This will do it. https://chessvision.ai.
There is also the Chessify app on the ios store where you can take pictures of chessboards and import the position.


What should I study? My ELO is 2050. I had not played chess for 4 years until I moved to Amsterdam. In Amsterdam I joined a chess club which has many strong players. Every Tuesday we play 90min + 15sec incremental games each other.(I played 6 games)

I noticed that I could not calculate well enough for the last 3 games which I lost. Also I do not have solid opening knowledge. I started to study tactics from chesstempo. Am I on the right track?

Whenever I haven't played for a while I go through a book with 200 mate in two exercises. Easy stuff, but quite a lot, just to get into gear again. Chesstempo will serve a similar function for you.

But that is just to shake off the rust and not blunder too much. To get back to the playing strength from four years ago or to become even stronger, you should rather train calculation instead of tactics. I.e. not just combinatorial vision but the systematic calculation of long lines. The Dvoretzky books have exercises for that, but those are pretty difficult.

The main point is that in my experience servers on which you solve timed problems aren't really suited to improve calculation. Even just picking random positions from these 10000 puzzles and calculating them like you would in a game is a better way.

You should also reacquaint yourself with your openings, by looking up your old repertoire lines and then play some internet blitz to get a feel for the variations again.

You are in the enviable position of living in Amsterdam so you don't really have to spend money on books yet. The Max Euwe Centrum has a library of chess books in many languages, entry is free and you'll find the newest books on every possible opening and avenue of chess improvement.


How does an engine decide which node to search first? This is a follow-up question to Randomness in Engine Play. SmallChess's answer indicates that in one instance, Stockfish searched a given number of nodes after 20s, and a different number in the other 20s, hence there is randomness.

The question: if each node is a given position, how does Stockfish decide which node to search first? Take for example the first half-ply. White has 20 possible first moves, so there are 20 nodes. I demand that Stockfish play a move after searching five nodes. Does this mean that Stockfish might only have evaluated 1. a4, 1. a3, 1. b4, 1. b3 and 1. c3 before it has to make a move? A systematic search like this would mean Stockfish hasn't evaluated the most common first moves however.

I imagine that, later in the game, there'd be a massive jump in the number of nodes per half-ply. That would mean that Stockfish would sometimes decides to make a move even though it hasn't finished evaluating every node in the half-ply. How would it know that it's searched the most promising nodes?

http://rebel13.nl/rebel13/ideas.html explains this well.

The basic idea is to order the moves based upon what the program thinks is the best move without searching.  This score is usually based upon mobility, piece-square value, center control, history, attacking potential, captures, and other elements the programmer thinks is important.  Just as humans base their candidate moves based on intuition and history, the computer searches the highest scoring move first.

If the computer is limited to only five nodes, then yes, the computer will only search the five highest scoring moves.  This time limit factor could cause to computer to miss a mate-in-one if it was scored poorly.  The first method to correct for this was to establish fail-safes.  These would cut short a search if the position became noticeably worse or significantly better.  The hope was to allow for more time to search more variations that might use the time better.  Other search algorithms, iterative deepening,  have improved the time management as they have a shorter length before they enact a fail-safe.


How much time should be spent on learning an opening? I know this can be a subjective question depending on the opening, but in general, should on spend time on a few openings at once or should one concentrate on one opening for a while and play it every chance they get?  In general, how long should one spend on an opening, including the variations?

You're right about this being a very subjective question. I've read a few books (sorry, can't think of good references) that suggest choosing a very limited set of openings to begin with. Use this exhaustively in every situation you play, whether appropriate or not. As you attack and defend in a variety of situations you will begin to learn the merits of the position in greater depth than simply reading about them.

As for how long to stick with it, my best suggestion (and this is indeed subjective) is to stick with the opening until you stop being surprised. Once you feel you've "seen it all", you're ready to branch out.

When you begin to spread to other openings, you may find it easier to use openings that can be transposed to from the openings you already know. The similarities will help you adjust more quickly and give you greater flexibility over the board.


Are trap games a good plan versus rated chess players or not? A lot of times I used to play trap games in chess; most of the times I won the game. But the my question is this: is it good strategy to play a trap game when facing a rated chess player?

I will assume that a "trap game" is an opening that contains a devastating trap if your opponent plays the wrong move.

What happens if your opponent does not fall for the trap? As long as you can still have a good game, it's ok to play a trap game.


How are the ECO codes for chess openings assigned? As an example, I will use the Ruy Lopez.

C60 is defined as 1.e4 e5 2.Nf3 Nc6 3.Bb5 as well as host of other Ruy Lopez variations.

C60 is also the Ruy Lopez - Cozio Defence, Paulsen Variation which is defined by the moves 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nge7 4.Nc3 g6

C66 is the 'Ruy Lopez - Closed Berlin Defence, Chigorin Variationwhich is defined by the moves1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6 4.O-O d6 5.d4 Nd7`

How do these codes get assigned?  In the case of the Ruy Lopez, are the codes differentiated after the move 3.Bb5?

It looks to me like someone just went in order of these started with the b pawn, the c pawn, the d pawn, the e pawn, and then indexed those. and then went the other side and said these were responded to by the b pawn, the c pawn, the d pawn.

Naturally, there is a more sophisticated classification of the whole deal. ECO stands for the Encyclopedia of Chess Openings. As with all encyclopedias, it has volumes. There are 5 volumes: A, B, C, D, E. Note that these correlate to the range of eco's which is A00 to E99. In your example, there are 40 entries for the Ruy Lopez (C60 through C99).

Each volume is broken down into a type of openings designated by,

Volume A: Flank Openings
Volume B: Semi-Open Games other than the French Defense
Volume C: Open Games and the French Defense
Volume D: Closed Games and Semi-Closed Games
Volume E: Indian Defenses

and in general, the main eco codes break down into

A
White first moves other than 1.e4, 1.d4 (A00–A39)
1.d4 without 1...d5, 1...Nf6: Atypical replies to 1.d4 (A40–A44)
1.d4 Nf6 without 2.c4: Atypical replies to 1...Nf6 (A45–A49)
1.d4 Nf6 2.c4 without 2...e6, 2...g6: Atypical Indian systems (A50–A79)
1.d4 f5: Dutch Defence (A80–A99)

B
1.e4 without 1...c5, 1...e6, 1...e5 (B00–B09)
1.e4 c6: Caro-Kann Defence (B10–B19)
1.e4 c5: Sicilian Defence (B20–B99)

C
1.e4 e6: French Defence (C00–C19)
1.e4 e5: Double King Pawn games (C20–C99)

D
1.d4 d5: Double Queen Pawn games (D00–D69)
1.d4 Nf6 2.c4 g6 with 3...d5: Grünfeld Defence (D70–D99)

E
1.d4 Nf6 2.c4 e6: Indian systems with ...e6 (E00–E59)
1.d4 Nf6 2.c4 g6 without 3...d5: Indian systems with ...g6 (except Grünfeld) (E60–E99)

Source: http://en.wikipedia.org/wiki/Encyclopaedia_of_Chess_Openings


What is it like to be a Twitch chess streamer? I want to make a Twitch stream channel with my friend, and I want to know what the experience is like. Can explain it better to me or share their knowledge and experience?

First, it would be interesting to know what your goals with the channel will be. If it is to have enough revenue that it can become your job, you will need to offer something that others are not already offering, or do what they are doing a lot better. You need some kind of "angle".

For most chess channels, the angle is that they are Grandmasters, and since I looked you up on FIDE.com for another question previously, I know that you are far from that (I am not trying to be mean there). The other channels that are very popular by weak players also have something in common: Cute girls with good personalities. Alexandra Botez and Gold Dust Tori come to mind. Frankly, Tori is so weak, I could not imagine watching her although I have seen her for a few minutes here or there when a chess.com broadcast I was watching ended, and my channel was "raided" (users that are automatically transferred to another channel). Be prepared to change your approach after some time if you not getting any followers.

I am not saying that you cannot do it, but you will need to find something that makes you very unique. One idea for someone else might be: If you had been about half your age, like 6, it could have been to follow the little boy from novice through to Grandmaster, and grow with him. You are considering trying to stream with a partner. Partners seem to do well here (and on radio and television). A partner allow for more conversation, and for you to bounce things off each other.

Once you have your idea, then there is patience, and promotion. Assuming that you want to make money (if just for fun to have a channel, then all bets are off...just have fun), you would need to understand that it would be a job. You will need to spend many hours streaming for little, or no, money in the beginning until you have a following. Unlike YouTube, Twitch is more about live playing against various opponents, and you discussing what it going on for the audience.

Did I mention that it is a job? (Yes, I know I did.) You would need to take it seriously, and be consistent about your streaming, and that means probably every day, 7 days a week in the beginning. Famous streamers, like Hikaru Nakamura, can take stream as they like since people will show up when they show up (Naka puts his schedule on Twitter, for example).

Promotion. You will need to learn how to promote your channel via social media so people can find you among the multitude of channels. You will need to read books and websites from experts on how to do that. I do not know much about this, but you would need to find out how the system for "raids" works. That might be about building personal relationships, aka partnerships, so established channels are willing to let you take their audience when they are done.

It is a numbers game: You will need follower first, and then maybe they can turn into subscribers. Not all subscriptions cost money since Amazon owns Twitch, and they allow Prime members one free subscription per month. I usually back chess.com or Naka, personally with my Prime membership.

I wish you good luck if you try to do this.

"Tips for becoming a Twitch video game streamer"