Can you recommend a dynamic, concrete, or easy-to-play line against the London System? I hate playing against the London because it allows 800 FIDE rated players to survive for 50+ moves.

By the way, I play the Grunfeld against d4, the Sicilian Najdorf against e4, and the triangle against most Nf3 systems. I also play the Ruy Lopez and the most mainline e4 lines there are for white.

So do you have a strong, venomous system that combats the London move order? I looked at 1. d4 Nf6 2. Bf4 c5 which I like for Black, but they can play 2. Nf3 first. Any recommendations? I accept fianchettos and systems where the light squared bishop gets developed.

Thanks in advance!

According to modern theory, playing the QGD as if you were white is the best option.  (That is, of course, just to sell more useless books.)

I play an early Bd6 to challenge this system, but the problem I experience is when they don't trade the bishops.

The logical plan is to play the KID.  The bishop will be "biting on granite."  When the time is right, pushing the e pawn will gain tempos on the Bf4 and Nf3, and since this system mostly develops the Bd3, a fork is possible.
Another popular theory is to exchange on d4 and plan for a minority attack.

None of these seem dangerous, but you can use their development system to expect certain moves.  You know that they won't be attacking with c4 and you know that they will place a knight on f3 (and later on e5.)  An early Bg4 to avoid the bad bishop, and, since they aren't attacking your center, this bishop won't need to be protecting b7.

Also possible is to develop your bishop before establishing the triangle formation.

These won't prevent long games, but it may provide you with positions that you are more comfortable with.


Chess tactics #6: Yugra Governor's cup again The one that I posted yesterday Chess tactics #5: Yugra Governor's cup wasn't the only blunder that happened yesterday in this tournament. In the game between Alexey Sarana (2426) and GM Pavel Ponkratov (2604) the following position was reached:

[fen "5rk1/1bn1q1bp/p2p4/2pP1P2/1rB5/2NQ2BP/RP3PK1/5R2 w - - 0 1"]

White has just played 25. exf5. How did Ponkratov win the game?

It seems like

   1. ... Bxc3 2. Qxc3 Rxc4 picks up a piece, because Qxc4 loses the queen to Bxd5+.


Definition of Soundness What exactly does it mean for a gambit to be unsound?  I see this term being used a lot but I have yet to come across a precise definition.

Is it enough for white to lose the  advantage that comes with being the first player?  What if black is better with best play but not winning?

How is soundness defined if black is the one playing the gambit?

Adapted from here.

A gambit is said to be 'sound' if it is capable of resulting in an advantage against the opponent. There are three general criteria in which a gambit is often said to be sound:

Time gain: the player accepting the gambit must take time to obtain the sacrificed material and possibly must use more time to reorganize his pieces after the material is taken.
Generation of differential activity: often a player accepting a gambit will decentralize his pieces or pawns and his poorly placed pieces will allow the gambiteer to place his own pieces and pawns on squares that might otherwise have been inaccessible. In addition, bishops and rooks can become more active simply because the loss of pawns often gives rise to open files and diagonals.
Generation of positional weaknesses: finally, accepting a gambit may lead to a compromised pawn structure, holes or other positional weaknesses.

An example of a sound gambit is the Scotch Gambit:

[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Bc4.

Here Black can force White to sacrifice a pawn speculatively with 4...Bb4+, but White gets very good compensation for one pawn after 5.c3 dxc3 6.bxc3, or for two pawns after 6.0-0 inviting 6...cxb2 7.Bxb2, due to the development advantage and attacking chances against the black king. As a result, Black is often advised not to try to hold on to the extra pawn.

An example of an unsound gambit is the so-called Halloween Gambit:

[fen ""]
1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.Nxe5?! Nxe5 5.d4.

Here the investment (a knight for just one pawn) is too large for the moderate advantage of having a strong center.


Online or Print Sources for Historical Games What are the best online or print sources for historical games? I am generally looking for pre-1930s games NOT by world champions, and, in particular, looking for games by some of the prominent women chess players of the time (Mary Rudge, Nellie Showalter, Harriet Worrell, etc.).

In addition to a handful of games at chessgames.com, you may find the following links useful:

About 35 games played in first international women's chess tournament held in 1897 can be found here. Games are in digitized form, in algebraic notation. The sources of each game (chess magazines of the time) are mentioned at the end of each game. You might be able to find these chess magazine pages at the Chess archeology website or by searching for the name of the chess magazines on archive.org. Using a similar approach, if you know the year in which the women players you are interested in played the tournaments, you can dig the games out from the archived magazines. These games will be in old notation, though.

A nice series of articles on women in chess published in a chess.com blog; contains a few annotated pgn games by women players (including the players you asked in the question).

Also, in reply to a comment you mentioned above (where do chessgames.com get their games from?), you will find the following answer in the FAQ page of chessgames.com:

The database has been constructed over a period of many years from PGN files obtained from free, public domain sources. Primary among these sources are:
* University of Pittsburgh FTP - one of the oldest and most complete archives of chessgames online.
* La Regence - archive of recent chess games, organized by ECO code.
* Britbase - archive of British chess games from the 1920's to present.
* Rusbase - the Russian cousin to Britbase.
* The Week in Chess (TWIC) - Mark Crowther's world famous source for brand new chess games.
* Lars Balzer's Homepage - A very well maintained list of places on the internet where you can download chess games.


Why would a player throw a game? So I am kind of new to chess and I have been playing online. I have been playing for a year and I consider myself a mediocre player, not too good and not too bad. Recently I got this invitation from someone to play a rated game. This person's rating is around 2100 so I said what the heck. Let's try it. As the game progressed, I saw that he was playing like a child. He made obvious blunders and simply offered me all of his pieces one by one. At first I thought maybe there is some deep strategy that I can't see but no. Now the game is about to end. I have a significant advantage in pieces and he will lose for sure.

My question is, has this ever happened to anyone? Or is this common in the chess community? Is this some weird strategy like how politicians try to throw elections if it is advantageous in that particular voting scheme or how players throw games if money is involved? There is no money involved, no tournament/prestige/title. If anything, he'll lose points and I'll gain them. I don't even know this person. We are just playing anonymously against each other online for the first time. Why would such a highly rated player play against a much inferior player and then lose that game...and it looks like he is deliberately losing.

Quite frankly it is boring and even a little condescending. I was expecting a much more exciting game.

So here is the game. My pieces are white.

[FEN ""]

1.e4 d5
2.exd5 e6
3.dxe6 Bxe6
4.d4 Bb4+
5.c3 Bd6
6.d5 Bf5
7.Bd3 Qe7+
8.Be3 Bg6
9.Nf3 Nf6
10.O-O Nbd7
11.Bxg6 hxg6
12.Re1 O-O-O
13.Bxa7 Ne4
14.Nbd2 f5
15.Nxe4 fxe4
16.Qa4 Nf6
17.Bd4 Qf7
18.Bxf6 gxf6
19.Qxe4 Rh5
20.Qe6+ Rd7
21.c4 Qxe6
22.Rxe6 Rf7
23.Rae1 Bxh2+
24.Nxh2 Rfh7
25.Rxf6 Rxh2
26.f4 Rh1+
27.Kf2 Rxe1
28.Kxe1

So what do you guys think of this game? Any and all comments welcome.

There are some possibilities that I can think of:

His 8 year old sister, dog, neighbor, etc suggested some of these 'great moves'
He was trying to handicap himself to make it more challenging
He tried something new or crazy, possibly to end the game quickly (e.g sacrificing his own pieces to expose your king or free his pieces)
Maybe he tried a chess gambit, first glance it appears you gain advantage, but this advantage is just an illusion.

My favorite is the Danish Gambit (it is rare that someone accepts it completely outside beginner level though)

[fen " w - - 0 1"]

1.e4 e5 2.d4 exd4 3.c3 dxc3 4.Bc4 cxb2 5.Bxb2

Update: now that I have seen the game, I can confirm it was a mix of points 3 (the move 23...Bxh2) and 4 (but he decided to improvise one instead of using an existing one). Maybe some of point 1 too.


Why is en passant possibility recorded in FEN regardless of whether there is a pawn ready to make the capture? If a pawn has just moved  two squares ahead, one records the square right behind it in the part of FEN for recording en passant possibility, regardless of whether there is a pawn of the opposite color ready to make the capture.

For example, the FEN for the position after 1. e4 is:

rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1

My question

Why is this done? It sounds superfluous, since an en passant capture can be made only on the very next move of the opponent's, so recording it as such when there is no pawn in position to make the capture seems unnecessary.

Is there some historical or technical reason for this?

Easier for everybody. No need to check enpassant possibility.


What is 'space' on a chessboard? I know, I know, this sounds like a ridiculous question, but bear with me.

As an example of my lack of understanding, let's take the advanced variation of the French defense.

 [title "Advanced variation of the French Defense"]
 [fen ""]

 1.e4 e6 2.d4 d5 3.e5

The opening books say something like "white advances their e-pawn to gain space in the center". Now, try as I might, I simply can't see where the extra space is that white has gained!

They can't use the f6 square or the e6 square as these are covered by pawns, knight and bishop. They can't use the e4 square as that is covered by black's e5 pawn. So where on earth is the extra space that white is supposed to have gained?

It's not a ridiculous question. Before discussing your precise example, let's cover some basic grounds:

Purely from an optimal play perspective: having more space translates into having more activity and thus more options for your pieces, and that's really the key point here. The more space your pawn structure provides, the more maneuvering possibilities you will have to re-route your pieces around the board to ever more optimal posts. Moreover, controlling more space also means eyeballing or covering your opponent's important squares, related to concepts such as "dark/light square control" in chess strategy. So it's really about the relative amount of space both sides control. For a trivial example, go to very basic cases, such as first moves, 1.e4: what is the point very naively speaking? Not only it activates some of your pieces, but it also potentially takes away options from black, namely, it stops black from establishing a pawn on either d5 or f5, therefore we say white is a tempo up, because it gets the first say in space control and thus partially dictates the types of subsequent positions.
As for general ways of defining it, not necessarily restricted to optimal play in chess strategy, you can e.g., define space in terms of the number of possible legal moves you have, or the number of squares that are under attack by your pieces, so on and so forth, all compared to the other side.

Your position:

 [title "French defense example:"]
 [Fen "rnbqkbnr/ppp2ppp/4p3/3pP3/3P4/8/PPP2PPP/RNBQKBNR b KQkq - 0 3"]

In your example, there are very clear differences in terms of piece-activity thanks to the advanced white pawns on d4 and e5 in contrast to black's lesser advanced central pawns of e6 and d5:

white has activated both bishops, whereas black's c8 bishop is facing a wall.
white has enabled both knights to be posted centrally on c3 and f3, whereas black's f6 square has been taken away, so the knight is bound to go via the e7 square, but you have both options of f3 and e2!
white's queen has a total of 6 legal possible moves at its disposal, black's queen is restricted to only 3! Specially Qf3, Qd3 and Qg4 all very useful and common moves for the queen, all of which are symmetrically impossible for black, because of the lesser space created by the central pawns (which in turn also disabled the c8 bishop in taking away the g4 square from white's queen!)
Last but not least, although both sides have committed to their central e and d pawns, black's prospect are further limited by the fact that in order to eventually create healthy space for their pieces, they're forced to undermine white's pawn chain with f6 at some point. Meaning black's further pawn development is also being limited here, but white's are not.

Now all is not lost, because space alone doesn't dictate the outcome of the game and all still depends on how you decide to use that space, but the moral here is that having more space means having more choices, both in terms of possible moves and possible strategies to pursue.


1. c4 vs c3 Sicilian I am a chess player ranked at around 1400. As white I play 1. e4 and am confident playing against most responses except for the Sicilian. I don't want to go into the main lines so I am studying the c3 Sicilian, but am realizing that there is a lot of theory I need to learn. A friend of mine recommended that I play a new opening altogether, 1 c4 that avoids a lot of theory. .

My question is this, would it be easier to learn how to play 1 c4 instead? What are some of the openings I need to know?

I think you should stop being afraid of your theory book, and concentrate on fighting your opponent in a game of chess. Especially rated at 1400, you need to experience interesting tactical battles, attacking chess, and basic strategic ideas.

Edmar Mednis wrote "A number of students have told me that they like to play 1.e4 except against the Sicilian. Such a 'complaint' makes no chess sense to me. I mean, 1.e4 is for those who like active, attacking play. Because the Sicilian delays black's kingside development while ignoring white's active development, attacking players should jump for joy when they see Black play 1...c5." (Practical Opening Tips)

He then goes over some lines involving: 1.e4 c5 2.Nf3 ... 3.d4 cxd4 4.Nxd4 ... 5.Nc3 ... 6.Bc4 against the main Black systems. Some of these Fischer used to play. The 2.c3 variation is also a good one.

Don't be afraid of main lines. Get an interesting position on the board (that's all a main line is - a position so interesting lots of people have played it) and fight it out. You will learn loads. Develop your tactics, and start to see the strategic ideas by playing the opening. Seek inspiration from your own games and those played by other people - not theory books.

(I had the same problem myself. I'm around FIDE 2050 now, and a 1.d4 player. All my life I've been afraid of the Slav. I got a book a few years ago advocating to play the main lines. So I plunged in with minimal preparation - my opponents never challenge me in a book line! But we get some interesting games, much better than the exchange Slav I relied on all this time.)


How to be a better tournament player? I have an upcoming tournament and I already started to prepare, but I have some questions about tournament play:

How to do better in tournament games
Should I adjust to my opponents' play
Do I need to study every player or just work on things ( opening repertoire, tactics,... )

If you are this Janjic, Slobodan P, I would say that you need to do tactics, tactics, and more tactics. Try to do 50 per day, spending no more than 2 minutes per tactic. At the lower mid-levels, it really comes down to who loses a piece first most of the time.

I want to suggest that as you do the tactics, REALLY try to concentrate as you do them, and do not just play a move that looks good, and hope that you are right....REALLY see it through to the end, and try to visualize what it going on...don't play "hope chess" (I HOPE this works).

I covered this in depth for all rating levels here.


Is it still back-rank mate when there aren't friendly pieces blocking? The definition of the back rank mate is:

  A Back-Rank Mate is a checkmate delivered by a rook or queen along the
  back rank in which the mated king is unable to move up the board
  because the king is blocked by friendly pieces (usually pawns) on the
  second rank.

For example white to move in this position

 [fen "6k1/5pp1/8/8/8/3B4/5PPP/4R1K1 w - - 0 1"]

King can't escape second rank, is this back rank mate?

What about this:

[fen "6k1/5bpp/8/8/2Q5/8/5PPP/4R1K1 w - - 0 1"]

What about this interesting black to move situation (its mate), is there a name for this mate?

[fen "6kr/5ppp/7N/2B5/8/6R1/8/1K6 w - - 0 1"]

First ask yourself why the differentiation of a 'back-rank mate' is meaningful.

Generalized patterns that we call 'tactics' have names because it helps us to learn from them and respond to them. For example, I personally find the distinction between 'pin' and 'skewer' meaningful because it helps to separate the concepts of attacking 'through' either a less valuable enemy piece or a more valuable enemy piece. Likewise, understanding that pins with enemy kings on the other side are 'hard', and pins with enemy knights on the other side are 'soft' helps to make you wary of 'desperado' attacks that might help break your pin.

Really a back-rank mate could be seen as just a partially smothered mate. But it's important to see the distinction because of how common it is, so you can be aware of preparing for it. It is an acknowledgement of the fact that at the start of the game, your king only has 6 possible moves (being on the 1st rank), of which 3 are taken up by pawns, leaving you with just 2 open squares if your other pieces have developed already. Even after you castle, your king can remain vulnerable because it has only 2 squares of freedom, and both of those are on the same rank - meaning 3 of the opponent's pieces can checkmate your king with no support!

So, is it helpful to consider your examples above 'back rank mates'? I would argue yes. To me, being wary of back rank mates simply means I need to make sure my king has an 'escape path' when necessary; it is not so critical for me to say "back-rank pawn only" mate vs "back-rank my pieces only" mate vs "back-rank-2-of-my-pawns-and-by-the-way-a-bishop-is-attacking-h7" mate. In all 3 of those 'back-rank sub-types', I have failed to provide my king with enough mobility to avoid a common mating pattern.

Edit to consider your new example of mate with a knight, on the back rank. I would say that is not a 'back rank mate', because it does not involve an attack along the back rank, by the queen or a rook. Without that key element, the mating pattern is simply very different.


How can I deal with defenses I don't like? I like to play 1. e4, as I favor open and dynamic positions, and feel comfortable with most black responses, but I there are some openings I don't like, e.g. Sicilian or French. My aversion might be unreasonable, but I would like to know how to deal with this situation psychologically. Should I play e.g. 1. d4 instead in order to avoid these responses at all? Should I study these openings and try to overcome my aversion? Should I voluntarily use "drawish" lines like the exchange variation in French? Should I play unusual lines in order to throw the opponent out of the book (e.g. f4 in both openings)?

No matter what your first move will be, you will always run the risk to encounter some openings you don't like. It's the same with endgames. At example, I do hate mating with bishop and knight, but I had to do it once to win the game. Should I have avoided that endgame or agreed to an early draw instead, just because I don't like it (and because I forget half the time how to win this bloody endgame)? Avoidance is no option, sometimes you just have to endure unpleasantness. Never throw away a game by drawing early only because you don't like the opening.

Secondly, don't play something to "punish" your opponents because they played something you didn't like. Your opponents will always try to play something which is unpleasant to you, like attacking your king and mating you ;) If you like the exchange variation of the French, then by all means play it. But if you play it just to annoy your opponent ("hah, that will teach you to play the French ever again..."), think twice. You are playing to win the game, not to eradicate the love for the French opening in the world! Only ever choose a line because it suits your goal (like getting a good position, winning/drawing the game etc.).

My suggestion is to look into the reasons of your aversion. Don't you like the resulting positions? Ask yourself why. Is it because you don't understand them or because your play is not as good in them as in other positions? Then you found a spot worth of improvement! Is it because you don't like the kind of play resulting from such positions (like too many or too few open lines, etc)? Nearly every opening offers lines to steer the game into different kind of waters. Have a look at some games of your unpleasant openings, pick the ones you would have enjoyed most to have played and then look deeper into the lines/systems that the White player employed there. In the long run, you need to hone your skills even in areas you are not interested in. For some people it's those boring closed positions, the next one can't stand pawn endgames, etc., but to become better, you have to master those situations as well. And as soon as you do, you will begin to like those situations. So this is the way to go to avoid unpleasant situations: Make them pleasant to you because you can handle them.

That said, I must say that if you are really unhappy with the openings your play produces, changing your opening repertoire might be a terrible good idea, indeed. Just don't expect you can avoid playing unwanted openings that way. Every opening move can lead to openings you don't like.


Typical Good Bishop vs. Bad Bishop endgame - how to decide if stronger side has a definite win Black here has 3 weak pawns; if any one of them falls - he will very likely lose the game as well. If he lets White king break through via c4-c5(d5) - White will also likely win. c5 pawn is a passed pawn, but is not going anywhere. Evaluations like "White is better" are not precise enough - is it possible via analysis to prove that White definitely wins? Or that Black definitely holds? Variations or plans for both sides are welcome.

White to move:

2k5/5b2/p7/P1p2p1p/P4P1P/2K2B2/8/8 w - - 0 64

With new analysis from user AlwaysLearningNewStuff, we can conclude this is a win for white,

The first critical position appears after 1.Be2 Kb7.

      [FEN "2k5/5b2/p7/P1p2p1p/P4P1P/2K2B2/8/8 w - - 0 1"]

       1.Be2 Kb7

Black defends everything at the moment, but the only moves that keep the position are Kb7-a7-b7. A simple triangle maneuver puts black in zugzwang.

     [FEN "2k5/5b2/p7/P1p2p1p/P4P1P/2K2B2/8/8 w - - 0 1"]

       1.Be2 Kb7 2.Kd2 Ka7 3.Kc2 Kb7 4.Kc3

Now black is in zugzwang and loses. The following lines illustrate this:

[FEN "2k5/5b2/p7/P1p2p1p/P4P1P/2K2B2/8/8 w - - 0 1"]

1.Be2 Kb7 2.Kd2 Ka7 3.Kc2!+- Kb7 4.Kc3 ( 4...Ka7 5.Bc4 Be8 ( 5...Bg6 6.Be6 Kb7 7.Kc4 Kc6 8.Bd5+ Kd6 9.Bb7+- Bf7+ 10.Kd3 )( 5...Bxc4 6.Kxc4 Kb7 7.Kxc5+- ) 6.Be6 Bg6 7.Kc4 Kb7 8.Kxc5+- )( 4...Bg6 5.Bf3+! Kc7 6.Kc4 Kd6 7.Bb7+- Bf7+ 8.Kd3 )( 4...Be8 5.Kc4 Kc6 6. Bf3+ Kd6 7.Bb7+- Bf7+ 8.Kd3 ) c4! 5.Kd4! ( 5.Bxc4? Bxc4 6.Kxc4 Kc6= ) 5...Kc7 ( 5...Kc6? 6.Bxc4 Bxc4 7.Kxc4+- )( 5...Kc8? 6.Bxc4+- Bxc4 7.Kxc4 Kc7 8.Kc5 ) 6.Bf3! Kc8 7.Bd1!!+- Kc7 ( 7...Kd7 8.Bc2! Be6 9.Ke5+-)( 7...Kb7? 8.Bc2! Be6 9.Ke5 Bd7 ( 8... Bg8 9.Bxf5+- ) 10.Kd5!+- ) 8.Bc2! Be6 9.Ke5 Kd7 ( 9...Bd7 10.Kd5!+- ) 10.Bd1! Bf7 11.Kxf5 Kd6 12.Kf6!+-

The important idea is that after 4...c4! White uses 6.Bf3! to restrict Black king. After 6...Kc8 White repositions Bishop on c2 with the move 7.Bd1!! so the decisive zugzwang can be achieved. After 12.Kf6! the rest is a matter of technique.

The analysis is kept as brief as possible in order to preserve space, since the rest of the winning moves can be easily found with an engine.


Where can I find these mentioned chess problems? In his article “The Horse Concoction", Tim Krabbe mentions retrograde analysis problems that involve placing 10 rooks, knights, or bishops on the board for a mate in 1. The 10 rooks problem shown (it also on site).  However, the other two by Henrik Juel and Guus Rol are only mentioned. Who made which is unclear, although suspect that it goes respectively.
Here is the relevant portion of the article.

"In the last few years this old idea, where all the pawns of one or even both sides promote to one kind of piece, had been taken up again by the Dane Henrik Juel and the Dutchman Guus Rol - first with Bishops, then with Knights. And when Goldsteen saw Rol's latest version of an earlier composition by Juel, something unusual happened to him: he was jealous. He was just pissed off that he hadn't thought of Juel's and Rol's ten-knight problem (add ten black Knights to a given position so that White can mate in 1)."

Can these problems be found online? I would love to see them out of curiosity and to learn more about retrograde analysis.

Henrik Juel's three "add pieces" problems listed above (together with a fourth one) are all to be found, together with detailed solutions in PDB, using the query: a='juel' and K='add pieces'.
Here is the superb fourth one, with its surprising solution...
[Title "Henrik Juel. Probleemblad, 5/1997. Add a unit. What was the last move?"]
[FEN "4k3/ppp1pp2/4pp2/8/3P4/3P2P1/1PpP1PP1/2K5 w - - 0 1"]


Should I be afraid of the Slav Tolush-Geller Gambit? As Black, after 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3, I like to play 4... dxc4 5. a4 Bf5, but I am afraid to play 4... dxc4 because of 5. e4, the Tolush-Geller Gambit (always followed by  5... b5 6. e5 Nd5 7. a4 e6)

  [StartPly "9"]

  [FEN ""]
  1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. e4 b5 6. e5 Nd5 7. a4 e6 (5. a4 Bf5)

I am a 1800 Elo player who likes quiet and strategic positions, so this gambit which leads to insanely sharp tactical positions is frightening me...

But is this gambit really sound?
Does it really give White enough compensation for the sacrificed Pawn?
Should I really be afraid of it?
Should I really abandon 4... dxc4 because of this gambit and choose something else instead (maybe 4... a6 the Chebanenko)?

It is quite sound in my opinion. As White I always welcome dc: Black surrenders the center, and asserting a control over it is well worth the pawn. I am not so much sure about 6. e5 though.


how much time is a pawn worth In bullet, blitz, and rapid chess having more time than your opponent is an advantage. I'm wondering if there have been any efforts to determine how much of a time advantage a pawn is worth. Or say a knight. Has anyone tried playing machine matches to figure this out? Since I frequently play speed chess this could be good to know. For Example: 1 pawn = 1 minute advantage in 5 min chess; 1 knight = 30 second advantage in bullet; etc.

This is a well known quote about pawns and tempi:

  A pawn is worth three tempi

So a pawn is worth 3 good, developing moves. Given that most games are 40 moves long then for bullet and blitz we have:

Bullet: 1 minute for all moves per side implies 1/40 minute per move, implying a pawn is worth 3/40' = 0.075' = 4.5''
Blitz: 5 minutes for all moves per side implies 5/40 minute per move, implying a pawn is worth 3*5/40' = 0.375' = 22.5''

This is a rough guide and the value of a pawn varies by position.


Why does 6.Bc4 prevent 6...e5 in the Sicilian Najdorf? [FEN ""]
[StartPly "12"]
[Title "What is wrong with 6..e5?"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bc4 e5

Please do not reply that it weakens the d5 square and allows the white bishop to attack f7. I am an expert player with lots of experience with the Open Sicilian from both sides in many variations. In view of the systems where Black plays e7-e5 even allowing the doubling of pawns after bishop takes knight on f6 it is not at all evident that this move is bad.

There is a related question about 6..e5 after 6.Bg5 without satisfactory answer for two years: Why does 6.Bg5 prevent 6...e5 in the Sicilian Najdorf?

The 2013 book on the Najdorf Sicilian by Zaven Andiasyan is a Black repertoire book which replies e7-e5 to anything except 6.Bg5 and Bc4 without a single line of explanation why not.

e5 is bad against the Fischer-sozin variation, because of 7. Nf5, which puts pressure on the d6 weakness.

Now granted, you could play Nf5 whenever black plays e5, whether you're playing Be2 (the classical system), or Be3 (the english attack).

So the real question is, what's the difference between:
e5 in the Sozin variation, and
e5 in the classical variation, f4 variation, english attack, etc. anything but Bc4 and Bg5.

The difference is, after white plays Nf5 in the classical variation, black has this amazing resource which is 7...d5.

If black plays e5 against the Sozin variation, 7. Nf5, d5 doesn't work because the pawn is capturable.

If black plays e5 against the Bg5 variation, 7. Nf5, d5 doesn't work because the knight on f6 is pinned, therefore the pawn on d5 is safe to capture.

The remaining question is: Why is d5 a necessary resource?

Well, d6 is going to fall and black will no longer play for a win because of the attack on the d file. He/she will have to worry and protect the d6 pawn while white goes for some kingside attack or whatever. After d5, black has no problems. Literally no weaknesses, none, and finally black can play for a win.

Also, in the classical system, after d5, 8. Bg5 is the best move in which black gets in d4. Doesn't that just look crushing for black? And, which side would you rather pick? Black!


Biggest Possible Material Advantage But Still Losing Assuming: Queen=9, Rook=5, Bishop=3, Knight=3, Pawn=1

The below position is evaluated at +411 for White but he still loses by force (mate in 9, pawn promotes to a bishop just for the fun of it)

Is that the maximum possible material advantage while still losing? Can you find a position with more than 411 material advantage and still lose?

[FEN "QQQQQbBk/QQQQQBQB/QQQQQRBK/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ b - - 0 1"]

1... Bxg7

I'm getting +518 for this.

That could be improved to +520 if we allow a black pawn on the 8th rank instead of the bishop, since this position is obviously already impossible for a number of other reasons.

Edit:
Found a better one.

QQQQQQNk/QQQQQQNp/QQQQQQKN/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ b - - 0 1

This is +530.


Can computer software that doesn't use databases still beat best in world? Are there strong chess engines that can beat most of the good chess engines without using databases (like opening databases), solely using brute force?

In the recent Nakamura - Stockfish match, Stockfish played with a one pawn handicap.

Additionally "According to match conditions, Stockfish was not allowed to access either an opening book or an endgame tablebase.".

Without opening database and with a one pawn handicap, Stockfish still beat Nakamura quite handily 3-1.


How to flip board in scid? I am using scid version 4.6.2. How can I flip the board such that I get black's point of view?

There should be a flip button somewhere, but I do not see it:

I've enabled all toolbar buttons as well:

So, for future reference, the option is under: Edit -> Setup Start Board..., or by pressing S.

Update: There is another way! Click on the 'menu' icon below the board (three horizontal bars), then on the what I see as a 'crop' icon (on the far right), and then following menu pops up:


Why is the 'classical' Nimzo-Indian called the Noa variation? I recently played 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 d5, and it was coded as the Noa variation of the Nimzo-Indian. There was a Josef Noa of Hungary, who lived from, 1856-1903, but his recorded games do not include a Nimzo-Indian, let alone this variation. Why is it named after him then?

The Oxford Companion to Chess says that the Noa Variation of the Nimzo-Indian was played regularly by Josef Noa, but that he reached the position after 1.d4 d5 2.c4 e6 3.Nc3 Bb4 4.Qc2 Nf6.


Which was the first televised/video-recorded WCC match? I was thinking about the way that chess has taken to being streamed recently and it got me wondering how far back one could go if they were to watch WCC matches instead of playing through them.

So which match was the first to be completely (not just one game or the awards ceremony, etc.) recorded as it was being played?

From a report by Harry Golombek on the seventh game of the Botvinnik v Smyslov world championship match in Moscow on 30 March 1954:

Television made its first appearance in the history of world chess championship matches during the course of this game, which was televised from 8 till 8.30 p.m.
Source: BCM, May 1954, page 141.

The 24-game match had 14 decisive games, 12 of the first 16, including a streak of 8 decisive results in a row! All the games were full of fight, and many of the games were of theoretical significance.


Why are rooks better than knights? Generally, rooks are considered to be much better than knights.  Why is that?  Is it a myth or are they really better?  Are there situations where a knights may be better that a rook?  I usually think that rooks enter the game a bit later and this reduces their value during the early stages of the game.

Rooks are more suitable for open games where there are open lines. Knight are better for more closed games. Knights have the benefit of jumping over other pieces and rooks have the ability to move quickly whereas knights move very slowly.

Also, remember that you can't checkmate with just a Knight and King, so Rooks are probably more powerful in the endgame especially when the board is wide open.


What are some stronger moves I can play next time in the King's Indian Defense? [fen ""]

1. d4 Nf6
2. c4 g6
3. Nc3 Bg7
4. e4 d6
5. Nf3 O-O
6. Be2 e5
7. O-O Nc6
8. d5 Ne7
9. Ne1 Nd7
10. Be3 f5
11. f3 f4
12. Bf2 g5
13. b4 Nf6
14. c5 Ng6
15. cxd6 cxd6
16. Rc1 Rf7
17. Nb5 a6
18. Nc3 Bf8
19. Na4 Bd7
20. Nb6 g4
21. Nxa8 g3
22. hxg3 fxg3
23. Bxg3 Nh5
24. Bf2 Ngf4
25. Nb6 Rg7
26. Nxd7 Qxd7
27. Kh2 Nxg2
28. Nxg2 Rxg2+
29. Kxg2 Nf4+
30. Kg1 Qh3 0-1

I won that game, but I feel like I got lucky. I blundered in this game. I feel that letting white capture my rook on a8 was a blunder. Also what if white captured g4 then I have to capture e4 with my knight. White then captures my rook at a8. I don't see any compensation for black for the lost of material. I also don't see how to continue the attack through this variation. What could I have done better as black against my opponent? What are some key ideas in the King's Indian Defense that I missed in this game? What concepts should I grasp from this game I played to become a better chess player and better using the King's Indian Defense? When is it the right time to give up the rook on a8 for an attack on the king side?

won that game, but I feel like I got lucky. I blundered in this game. I feel that letting white capture my rook on a8 was a blunder

Everything you said was correct.

  Also what if white captured g4 then I have to capture e4 with my knight. White then captures my rook at a8. I don't see any compensation for black for the lost of material.

Again, I agree with your conclusion.

  I also don't see how to continue the attack through this variation.

You can't, because White plays Rc7 and keeps everything under control. Even if you "get" classical ...Bh3 sacrifice he will have Rxc7+ in that setup and your attack is dead. Bishops and knight will easily repel your minor pieces, not to mention that extra rook...
Since it was long time since I played actively KID ( both as Black and White ), I had to check theory as well. You missed the key move 19...Nd7! which stops White queenside action in its tracks, in my opinion. This is also the move theory recommends.

  What could I have done better as black against my opponent?

I think your first mistake, and very serious one, was 19...Bd7?!. I would simply follow theory and respond with 19...Nd7!, stopping White's shenanigans at queenside. His attack is severely slowed down, while you can continue the attack with ...h5. This is the only important moment you can use in this game to improve.

Aside from that, you made some serious blunders he could have exploited. After he took the rook the game was over, but you managed to "come back". In many occasions you gave him a chance for turnover, which is a result of poor combinational skill. You need to practice more, especially when you play this opening, and especially when you play this line. Tactics is everything for Black here! See the comments in the game below to see all the mistakes and suggested improvements.

[Title "Game analysis"]
[fen ""]

1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 e5 7.O-O Nc6 8.d5 Ne7 9.Ne1 Nd7 10.Be3 f5 11.f3 f4 12.Bf2 g5 13.b4 Nf6 14.c5 Ng6 15.cxd6 cxd6 16.Rc1 Rf7 17.Nb5?! ( 17.a4!? ) 17...a6 18.Nc3 Bf8 19.Na4 Bd7?! ( 19...Nd7!? ) 20.Nb6 g4? ( 20...Rb8!?+/= ) 21.Nxa8+- g3? ( 21...Qxa8 22.Rc7+- ) 22.hxg3 ( 22.Nc7!? gxf2+ 23.Rxf2) 22...fxg3 23.Bxg3 Nh5 24.Bf2 ( 24.Bh2!? Bh6 25.f4 Nhxf4 26.Bxf4+- ) 24...Ngf4 25.Nb6 Rg7 26.Nxd7?? ( 26.g4!+- Nh3+ 27.Kh1 Nxf2+ 28.Rxf2 Qxb6 29.Rh2 ) 26...Qxd7?? ( 26...Rxg2+! $8 27.Nxg2 Qg5-+ ) 27.Kh2?? ( 27.g4!+- ) 27...Nxg2?? ( 27...Rxg2!+ $8 28.Nxg2 Qh3+ 29.Kg1 Qxg2# ) 28.Nxg2?? ( 28.Rc7!! Qc7 29.Nxg2+- ) 28...Rxg2+ 29.Kxg2 Nf4+ 30.Kg1 Qh3 0-1

  What are some key ideas in the King's Indian Defense that I missed in this game?

You missed nothing, push ...f5 -> deliver checkmate or die. The concept is easy to grasp :)

The only time you sidestep this pattern is in Yugoslav attack, but that is a different story ( White there goes for fianchetto with g3 + Bg2 ). In that case you prepare exchange sacrifice with ...Rxb2!, but this is off-topic here. If you need further questions about this line post them as a new question.

  What concepts should I grasp from this game I played to become a better chess player and better using the King's Indian Defense?

You can't play this line unprepared, you must know theory of this line very well.

This line is so forced that one wrong move will cost you the game. Already after 19...Bd7?! White stood better! You had no counterplay after that, and if you played ...Rb8 he could simply take your light-squared bishop and destroy every mean of counterplay you have ( the point of this line is to sacrifice that bishop for h3 pawn ). Without your key attacker, your attack would be dead, while he would first bolster his kingside, and then demolish you on the queenside, since you would have no natural kingside counterplay.

Second thing, your tactical skill must be very high, because this line relies solely on that. There are no "hidden gems" it is raw and simple -> mate or die. You missed several times clean win which gave him the chance to win the game. I hope you will understand just how devastating blunders, or even imprecise moves, can be in this line, so please sharpen your tactical skill.

Third, play "clean chess". After 27.Kh2?? you had "clean victory" with 27...Rxg2+! 28.Nxg2 Qh3+ 29.Kg1 Qxg2# yet you decided to complicate with 27...Nxg2?? after which he could have won the game with 28.Rc7!!. Always aim to destroy opponent's counterplay, especially in these positions. If you have a queen and pawn versus rook, give the queen for the rook and win simple pawn endgame. In this opening, and in this mainline, there is always venom in position and "playing with fire" can backfire, in view of you stalemating the opponent or not seeing some cheap tactics. If you have a forced win, then by all means, win by force!

  When is it the right time to give up the rook on a8 for an attack on the king side?

Only if you are certain that your attack is so strong that it will at least get you perpetual check or will win you back the material. Other than that, forget it!

SUMMARY:

Well played, keep sharpening your tactical skill and learn theory to the last book move. Always aim to win the easiest way because this line is minefield and you never know when you will allow your opponent to play some crazy intermediate move that will give him magnificent comeback ( or maybe you will blunder a cheap tactical shot ).

If you have further questions leave a comment. Best regards.


Does some GM or notable coach consistently employ "hand and brain" as a teaching tool? I've seen some streamers do what they call "hand and brain", meaning that one person plays while the other chooses the kind of piece that they must move. All cases I've seen were intended for having fun. But it got me thinking about how effective would this be as a teaching tool.

My question, at heart, is: "Is playing hand and brain with a student an effective teaching tool?" Since this is probably too opinion-based, I only ask if there are cases of GM's/notable coaches that employ it as a teaching tool consistently. If there are references attesting to it being an effective teaching tool, those are of course appreciated.

As an IM and experienced chess coach I can say I only use it in play and for fun.
Serious training should be learning concepts and solving a lot of puzzles.
The only time I do use it is when one person is clearly stronger than the other and the weaker side needs some help. Especially absolute beginners who completely mess up all my plans are my favorite partners!
In theory of course you could use it once in a while as a training exercise, the players can learn from the plans of the others, but other than that I do not see any big use. Sorry, I do think it's fun, but fun and use are different.


Overcoming severe time troubles I started playing chess 2 years ago and ever since I started, I have experienced consistent time troubles. Recently, I gathered some data from my 40 most recent rapid 10+0 games, and concluded that I am ~2.08 minutes behind my opponent at around the midpoint of the game.
This is absolutely horrible ! In one game I was 6 minutes behind, compared to my opponent. While the best time advantage I have had is 1.3 minutes. Only in 4 of the 40 games I had a time advantage or equal time, so in conclusion,

in ~90% of my games I am behind on clock of about ~2.1 minutes halfway through the game.

As a result, I can't play blitz (3 minutes) at all, even though I wish I could, since I have to start pre-moving way before my opponent enters that stage of the game. Which further explains my rating discrepancy of 1700 in blitz while 1930 in rapid, on Chess.com...
I think the main reason why I am so consistently behind on time stems from my anxiety of missing a tactic or just blundering something. I really want to fix this problem, but it is just so hard. Has anyone experienced the same thing as me? How have you overcome this problem, and what are available resources for a player like me ?

It doesn't matter if you spend more time than your opponent in a game. What matters is that you're spending the time effectively. The more complex the position the longer it's going to take to find the right move.
Where are your spending time time? And why? What is it you are thinking about? Are you double-checking, or triple checking your analysis? Or are you analysing as many moves as possible? Also look at the types of position you spend more time on: is it opening moves, is it positions right out of the opening, is it tactical positions, quiet strategic positions, unbalances positions, dynamic positions, or maybe positions you feel like you have a substantial advantage and you're trying to find a win?
The key is to bring discipline into your thinking, and train yourself to make a move quicker. First step is to figure out which position/moves the time is being spent. Then to figure out why. That why could lead you to identifying lack of knowledge/experience of a particular type of position -- maybe a weakness in your play. That means you can train yourself to get better at such positions, gain some confidence, and make it easier to find the right move quicker.
However, if you are spending the time double- and triple-checking your calculations, then it's a confidence issue. Something like Kotov's book "How to Think Like a Grandmaster" might help, to start training yourself to analysing a variation once, and only once, and to trust your calculation abilities. Perhaps calculation training is all you need.
If the reason for the time being spent is in the middle game trying to find a plan, then finding annotated games by grandmasters in the same or similar openings might be the solution, to give you more familiarity of the positions. That will help build an instinct as to the right kinds of moves and plans to play.
If you're spending a lot of time in the opening, then maybe spending time studying various opening systems you are playing to get a better understanding of them, e.g. playing through annotated master games.
And a steady diet of calculation, both tactics puzzles and endgame calculations. Chess is very much a pattern-recognition problem at the human level. And discovering patterns in study will help spot them in play. Building that instinct to the correct move, and then using calculation to verify your instinct is correct -- that's the Magnus Carlsen school of chess.


Eight pawns vs seven exercise: how to win? I had been thinking about exercises to help players <1400 gain confidence. For instance, they should feel confident they can always win with queen and king vs king, or rook and king vs king, even against Magnus Carlsen. They should also feel confident they can win with a bishop and 8 pawns vs 8 pawns.

So I lazily took all the pieces off the back ranks and removed black's king pawn, to give an exercise with king and 8 pawns vs king and 7 pawns. I figured winning a pawn up in a pawn endgame is a useful skill to know, and it should not be too hard.

[FEN "4k3/pppp1ppp/8/8/8/8/PPPPPPPP/4K3 w - - 0 0"]

However, initial desultory poking around showed Black may be able to sit tight and form a barricade. This could be instructive for a beginning player, but it also might be too intimidating.

While this probably won't happen in actual play (exchanged pieces mean there is probably at least one line open), this is a non-trivial case worth looking at, as Black could quite possibly establish a blockade down two pawns (you can ignore the two backwards pawns--I saw this pawn structure in a recent video of Ben Feingold's, about his 2019 Foxwoods tourney.)

[FEN "8/4k3/1p4p1/p1pPPp1p/P1P2P1P/8/4K3/8 w - - 0 1"]

What is a good strategy for White to minimize the possibility of blockades? Also, what is Black's best strategy to push pawns and maximize the possibility of blockades?

I figured winning a pawn up in a pawn endgame is a useful skill to
  know

It is a useful skill to know and an even more important skill to know is when a pawn-up endgame is a win and when it is a draw and when it could be either depending on who is to move first. This is a vital skill because it stops you from swapping off into a drawn king and pawn endgame when you are a pawn up.

  I had been thinking about exercises to help players <1400 gain
  confidence.

When it comes to building confidence in pawn-up endgames for <1400 players this is where you / they should start. This is a win for white if it is white's turn and a draw if it is black's turn.

[FEN "4k3/8/8/8/8/8/4P3/4K3 w - - 0 0"]

This teaches you the importance of:

The opposition and
Getting your king in front of your passed pawn not
behind

In terms of preventing (or aiming for) drawing blockades the <1400 player needs to know this position and why it is a win for white if it is white's turn and a draw if it is black's turn.

[FEN "8/ppp3k1/8/PPP3K1/8/8/8/8 w - - 0 0"]

This teaches you that it is the position of the pieces which is key not material balance. White to play wins by sacrificing a pawn or even two depending on black's response.

Finally, Capablanca's Position:

[FEN "6k1/7p/8/8/8/8/6PP/6K1 w - - 0 0"]

It is a win for white but if black knows the ending it is very easy for white to go wrong and end up in a drawn position. Many white players much stronger than 1400 would struggle to win this against a knowledgeable black opponent.

All 3 of the positions above could arise from the position in the question. All 3 have far fewer pieces and so are much simpler but are far from straightforward. Mastering them first would be a good first step.


Can Black draw this endgame? I was playing this game just a few minutes before posting this, and tried to save the game by entering the following endgame:

[Title "Black to move"]
[StartFlipped "0"]
[fen "8/6k1/1p2Kn1p/7P/1P6/5B2/8/8 b - - 0 1"]

I intended to sacrifice the knight for the b-pawn and then get theoretical draw by entering the following endgame :

[Title "Theoretical draw"]
[fen "8/6k1/4K3/7P/8/5B2/8/8 w - - 0 1"]

In the game, I played 1...Ne8 with the intention of posting it on d6. Then I could defend it with my king ( on the dark squares of course ). White can break this blockade with zugzwang ( he can make proper bishop moves to achieve this ), but I believe that Black has sufficient squares at his disposal to defend.

Is there a way for White to breach my defense that I have missed?

To me, it looks like your plan is to move your king forward to d6. After he takes your pawn, you play Kd6 keeping opposition and blocking the pawn advancement with the Knight on c7. Looks dead drawn after that.

[Fen "8/6k1/1p2Kn1p/7P/1P6/5B2/8/8 b KQkq - 0 1"]

1... Ne8 2. Kd7 Kf7 3. Kc6 Ke6 4. Kxb6 Kd6 5. Ka5 Nc7

[Fen "8/2n5/3k3p/K6P/1P6/5B2/8/8 w - - 3 6"]


Help me find this Lasker Chess quote I remember a few things from his saying - that he can produce a class A player out of an amateur in a span of so and so hours. I remember reading something along these lines, and I guess it's Lasker's quote, but my memory seems to fail me.

Chapter "Final Reflections on Education in Chess"

page 373 in this pdf file:Lasker's Manual of Chess


Computer endgame strength without tablebases I have seen that engines aren't particularly strong in the openings without access to a book.

How strong are modern engines in the endgame when they are not allowed access to tablebases?  E.g., can a computer typically win those difficult endgames such as KQ vs. KR and KBN vs. K in blitz games?

First, I'm not convinced that engines are necessarily weak without their books.  Without an opening book, modern engines might not play the most testing lines, or lines that would get them into a position where they thrive, but any top engine will still crush any human GM without an opening book.

As an interesting aside, if you leave your engine on for a while, it usually finds the Spanish Four Knights as the best line from the starting position, but I digress...

In the endgame, it totally depends on the engine and the position.  Without tablebases, engines might not know that a rook pawn and wrong bishop is only a draw.  If the programmers added that exception, then they'll figure it out, but otherwise, they might trade down thinking that they'll win with an extra bishop and pawn only to draw via the 50 move rule.

In more elementary endgames, like KBNvK, the stronger side will almost always win.  The longest mating sequence is 33 moves if my memory serves.  Most engines will stumble onto a forced mate in that time because their heuristics will have them make good moves that get closer to mate (and they can probably see 15-20 moves deep).

In terms of KQvKR, the stronger side will almost always win against a human.  Humans are pretty bad at defending this position, and the computer will instantly see ways to pick off a loose rook.  Against another computer, it's a little bit harder, but as Wes says in his answer, it is still likely that the stronger side would win (the Philidor maneuver is only ~5 moves long, plenty short enough for the engine to see it) given enough time.


What age is too old for becoming a good international tournament player? I am around my 30s and my ELO is 1350. I have attended many national tournaments, but I have very few international tournament experiences, one of which did not go very well.

I love my job, but I also enjoy playing chess very much. Specifically, I love the atmosphere of the tournaments.
Since I am not a citizen of the country I currently live in, I am not able to attend most of the national tournaments, and that leaves me with some international tournaments to attend with my online FIDE ID.

I am not looking to be a professional chess player, but I just want to be a challenge for mid-level players, whose ELOs are around 1500s.

Given the fact that attending an international tournament costs one time and money, my question is:

  Am I being a stargazer (or simply put, a fool) by attending
  international tournaments, or can I somehow improve my game to compete with players around the world?

Please note that I am not looking for something that is obviously out of my reach, such as having a full-time job and standing at top 5% in an international tournament.

I am older than you and my ELO going up every year - sometimes very slow - sometimes very fast - no matter who play chess live longer as scientists as the best runners :)

I am sure you will not learn chess by playing tournaments - you can learn chess by training - you will improve skills faster if you train more self and analyze more games. You will finally play better tournaments.

Playing games is slow method of training better is puzzles, learning ending games, openings, middle games, watching and reading master games analysis, analysis of skill weakness and errors.

Looking games of other players is also good - you can study much more position than playing. You can train little playing long chess games - or fast to learn openings.

To improve skills replace playing with training.
Trainers can improve you skill too but if you train self (everyday).

It will improve you skills in five years I think - who knows you can become 2000 ELO player if you have enough passion and self training skills :)

You should think like Magnus Carlsen when was 12 years - check where is your limits - tournaments is only exams of your skills - tournaments should played regular too to see own weakness.


What is a critical variation? Sometimes I hear that a critical variation in a certain opening was avoided and instead a solid variation was chosen. Can someone explain to me what a critical variation is? Maybe also explaing in the process what a solid variation is?

A critical variation is one that the evaluation of the current position depends on.

Take the Morra gambit:

[FEN ""]

1.e4 c5 2.d4 cxd4 3.c3

Is the Morra gambit a correct opening, or has white made a mistake? It does sacrifice a pawn, so the evaluation probably depends on whether white gets enough compensation after 3...dxc3. So that is the critical move. It's also the riskiest, because white does get some open lines and development, so he can probably at least set up some threats in the short term.

3...d3 is another move, declining the gambit. White doesn't get quite as quick development, but he's not a pawn down either. After this it's likely that the position is more or less equal, and it's just a game of chess. This is a move to play if you want to avoid risk, but it's not the place to look for a refutation of the Morra. So it's not critical.

A solid move is the oppositie of a risky move.


Average centipawn loss I had no incurracies,blunders or mistakes then also my centipawn loss was 48.

What is the problem here or I have misunderstood average centipawn loss.

You can have a look at that game at lichess.
Link to the game: https://lichess.org/fhvYi9SS/black

Average centipawn loss is the difference of your move to the best computer move averaged over all moves.

Inaccuracies/Mistakes/blunders as defined per lichess are moves that are at least 0.5=50 centipawns / 1=100 centipawns / 3=300 centipawns worse than the suggested computer move.

This rule is not strictly enforced in situations where you have a clear winning position and a choice of several good moves.

So if you have a choice between a move that leads to +10 advantage (best computer move) and +9 advantage this will count to your centipawn loss, but will not show up as mistake.

Even without it, it is possible to collect centipawn losses < 50 that don't show up as inaccuracy.


Is KQB vs KP generally sufficient to force a selfmate? User Hauke Reddmann noted in a previous answer that there should be a straightforward way to secure selfmate against a substantially weaker opponent (i.e., force them to checkmate you):

win all the material of your opponent, except a safely blocked pawn. Then force your own mate by zugzwang. The minimum material needed is KQB/KP.

I queried a Problem Database for White to selfmate against Black with KQB vs KP, and found 17 such positions. All of these, however, seem to require Black's pawn to be a Knight pawn (on the b or g file). There may also be some other patterns that universally hold (does the White Bishop have to be the same color as the Black pawn's promotion square?).
My question is as follows: is it generally possible to force a selfmate with KQB vs KP (for example, we may take a randomly selected position like the below), or is it a requirement Black's pawn should be a Knight pawn? If it is generally possible to force the selfmate, what procedure should one follow to do so?
[Title "KQB vs KP, White to play & selfmate if possible"]
[FEN "1Q1B4/8/6K1/3k4/3p4/8/8/8 w - - 0 1"]

Note: 'generally' means 'exceptional circumstances notwithstanding', such as for example if Black's pawn is so far advanced that it threatens promotion, or being so placed as to force White to capture it shortly, etc.

That one is a no-brainer: with a knight pawn the white king can stand in the corner, and be blocked in with just the bishop. This is impossible with another pawn - you must block both e.g. b1 and d1 and need a third White piece. (After all, Black must be forced to play d2#, so Qb1/Bd1 won't suffice!)
EDIT: Considering other material, if I recall correctly, KQR vs KQ is sufficient for forcing selfmate. (Again, check PDB.) A request at MatPlus Forum came up with this gem (Black can promote into all four pieces, always leading to a selfmate in 7 more moves):
Look for 1st prize
I.e. you, not surprisingly, can force a self mate with Black only having an e-pawn and White a bit more of material.


Position of pieces in square Is there a rule on how accurately pieces have to be positioned within a square? Can they touch the border for instance?

There are no FIDE laws governing these items for very obvious reasons.

FIDE does not legislate the size of the board, the squares or the pieces for ordinary play, nor the colour of the board nor the pieces. Since the pernickety days of Bobby Fischer these kind of things can be legislated for in something like the World Championship according to the demands of the players but it is unusual.

If you don't legislate for the size of the board, squares and pieces then it is nonsensical to start legislating for how pieces must be positioned within their squares. Obviously if you happen to be playing with kings whose diameter matches the width of a square then the king is going to be touching at least 2 sides of the square.

The FIDE laws of chess do give the following relevant guidance in the Preface:

  The Laws of Chess cannot cover all possible situations that may arise
  during a game, nor can they regulate all administrative questions.
  Where cases are not precisely regulated by an Article of the Laws, it
  should be possible to reach a correct decision by studying analogous
  situations which are discussed in the Laws. The Laws assume that
  arbiters have the necessary competence, sound judgement and absolute
  objectivity. Too detailed a rule might deprive the arbiter of his
  freedom of judgement and thus prevent him from finding a solution to a
  problem dictated by fairness, logic and special factors. FIDE appeals
  to all chess players and federations to accept this view.

The one line summary of that is not too hard to understand -

"Use your common sense!"

On your turn you are allowed to say "j'adoube" and adjust as many of the pieces as you like as may your opponent when it is his turn. However if you continue to do this repeatedly you may find that the arbiter comes and first warns you for disturbing other players and then starts penalizing you.

EDIT: For a real world example of pieces touching and crossing edges check out this Youtube video of a game between IM Basman and GM Fodor played in a FIDE rated rapid competition in August 2016 - https://www.youtube.com/watch?v=HYTy7xAT6uU .

The game starts just after the 3 minute mark on the video so start watching from about 2:45. Note the black c pawn which is 2/3 on c7 and 1/3 on c6. This doesn't disturb white who makes his first move without adjusting black's wayward pawn. It does mildly disturb black, though, who adjusts the pawn without saying j'adoube. His first move is b5 and the c pawn is adjusted en passant, as it were, with a backward nudge from his middle finger. Adjusting like this makes it clear that there is no intention to move the piece.

Now scroll forward to about 34:50 when white plays exd7. Note the white pawn on d7 is fractionally over the line into d8. Black plays Qxd7 and again the black queen is partially in d8. Both white and black players are unconcerned. Black plays Qb7 and again the queen is over the line and just edging into a7.

Scroll forward to the 40 minute mark and watch white play BxRc8. Note the bishop is just fractionally over the edge of the board. The black queen is still 90% in b7 and 10% in a7.

Both players, internationals in their own right, have no problems with this.

Note that the Youtube channel belongs to Adam Raoof who runs these monthly FIDE rapid tournaments. He is a FIDE international arbiter who has officiated at World Candidate match level and is a qualified FIDE international organizer who makes a living running and organizing FIDE rated chess competitions.


What are the main differences between 6...Bb4 and 6...Be7 in the Panov-Botvinnik attack? After the moves 1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Nf3, what are major differences in plans and variations for Black between 6...Bb4 and 6...Be7?

[FEN ""]
[StartPly "11"]
[StartFlipped "1"]

1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Nf3 Bb4 (6...Be7)

Currently I use 6...Bb4 and play against an isolated d-pawn or hanging c and d pawns. I understand these plans quite well. But often Black concedes the bishop pair and is left with a bad light square bishop, which I think is a major weakness.

According to the Game Database of ChessTempo, the mainlines of 6...Bb4 and 6....Be7 are quite similar:

6....Be7 7.cxd5 Nxd5 8.Bd3 Nc6 9.0-0
6....Bb4 7.cxd5 Nxd5 8.Bd2 Nc6 9.Bd3 0-0 10.0-0

Remarkably, the main move for the second line is 10....Be7, which transposes to the first line, but with an extra Bd2 for white. For instance, Nakamura-Wojtaszek and Motylev-Jakovenko.

Instead of 7.cxd5, white can also play 7.Bd3. In this case it is difficult to tell whether the bishop is better placed on b4 (to have the possibility to take on c3) or on e7 (to protect against the pin after Bg5).

Edit by Evargalo: The logic behind Black wanting the White bishop on d2 and not c1 is a bit complicated: In the variations with the bishop on c1, the main line (after 9.0-0 Nc6) is the logical 10.Re1, where there is a lot of theory and Black has to work hard to equalize. With the bishop on d2, however, 11.Re1?! is a dubious pawn sacrifice after 11...Ndb4! 12. Bb1 (or Be4, or Bf1, or Bc4) Nxd4, because the Bd2 interferes in the Qd1-Pd4 connection. Thus the main lines are 11.Qe2 or 11.a3, which are less direct although the opening debate remains open to this day.

Objectively speaking, the values of 6....Bb4 and 6....Be7 are probably similar. Therefore, choosing between both moves is more a matter of taste.

Note that the position after 6....Bb4 can also arise after a transposition from the Nimzo-Indian, which is the subject of another Stack Exchange question.

      [StartPly "11"]

      [FEN ""]
      1.e4 c6 2.d4 d5 3.exd5 cxd5 4.c4 Nf6 5.Nc3 e6 6.Nf3 Bb4 (6...Be7 7.cxd5 (7.Bd3) Nxd5 8.Bd3 O-O 9.O-O Nc6 10.Re1) 7.cxd5 (7.Bd3) Nxd5 8.Bd2 Nc6 9.Bd3 O-O 10.O-O Be7 11.Re1?! (11.Qe2) (11.a3) Ndb4 12.Be4 Nxd4


Time out question in a drawish endgame With some extremely rare exceptions, KNN vs KR endgame should be a draw. However, I am wondering what if this endgame happens in a game with no increments. I think the following will happen at chess.com:

If KNN runs out of time, KR wins.
If KR runs out of time, it is a draw.

Isn't this unfair since both sides do not have reasonable winning chances. It seems to me that in this endgame, time out rule favors KR, though KNN is 1 point up in material (if each knight is counted as 3 points and each rook counted as 5 points).

I think the following will happen at chess.com:

If KNN runs out of time, KR wins.
If KR runs out of time, it is a draw.

If chess.com abides by the FIDE Laws of Chess then this is false.
If the side with K+R runs out of time then they lose. K+R vs K+N will also lose. This is the relevant article:

6.9 Except where one of Articles 5.1.1, 5.1.2, 5.2.1, 5.2.2, 5.2.3 applies, if a player does not complete the prescribed number of moves in the allotted time, the game is lost by that player. However, the game is drawn if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves.

Here is the relevant helpmate position for K+N vs K+R. No second knight is needed.
[FEn "kr6/2N5/K7/8/8/8/8/8 w - - 0 1"]

Isn't this unfair?

If what you say is correct regarding chess.com's interpretation of the rules then, of course, it is grossly unfair. They would be much fairer if they abided by the FIDE Laws of Chess.


How can I check the Stockfish version? I downloaded Scid vs PC to analyse my games and I want to check what version of Stockfish is included - how can I check if it is Stockfish 6?

Double-click on the Stockfish executable, type "uci" (without the quotes) and hit Enter. You should get some output, near the top of which should be a line beginning with "id name", and this line gives the name of the engine, including the version number. (You may need to scroll up to see the "id name" line, if there's a lot of output.)

The same method works with any UCI engine.

Note that the Stockfish executable supplied with Scid vs PC is in the bin\engines\stockfish subdirectory of the Scid vs PC installation directory. The version of Stockfish included in my (recent) copy of Scid vs PC identifies itself as Stockfish 240813 64, which is a bit odd (perhaps it's a version compiled from source by the developers of Scid vs PC), but the file date suggests that it's roughly the same as Stockfish 4.


Which collections of pieces are legal? Call a collection of (white and black) chess pieces legal if it occurs in the position of a legal chess game. For example, KQRRBBNNPPPPPPPPkqrrbbnnpppppppp is the collection at the beginning of the game. It seems any subset of this (still containing the two kings) is possible as well. But sometimes you can have lots of promotions, so for example Kkqqqqqqqq is possible if black promotes all eight pawns to queens while all other pieces are captured.
Which collections of pieces are legal?
This answer on MathOverflow conjectures/states without proof that the legal collections are those that can be obtained from the starting collection using the following two operations:

Delete any (non-king) piece and promote at most one white and at most one black pawn.

Delete a pawn and promote at most one pawn of the same color and at most two pawns of the opposite color.

Is this characterization correct?

Yes the characterization is correct, and there are 58,084,310 legal collections in total.
To make headway, we need the right level of discourse, avoiding loss of accuracy while avoiding diving into trivialities.
Necessity & sufficiency of the deletion moves
Two kinds of operation were suggested to be necessary & sufficient to reach all legal collections:
(1) Delete a (non-K) officer & promote at most 1 wP and 1bP
(2) Delete a P & promote at most 1P of that color and at most 2Ps of the other color.

Firstly, the two criteria are necessary. To unblock a file a capture must take place. Capturing an officer will allow both pawns from a file to promote. A pawn capturing a pawn from a neighbouring file is more efficient, as it allows three pawns to promote.
The condition is also sufficient, as can be seen by dividing up the board into 4 pairs of files. We have to make assumptions that the kings can keep out of the way of the action. See later for an example which explores the validity of this assumption.
"Supply & demand"
Maybe worth moving on to the question of which collections are achievable in this way:

Count the number of visible "non-starting officers" for each side (queens beyond the first; other officers beyond the second of that type): N_w & N_b
Count the number of "awol pawns" on each side: (pawns morphed into NSOs aren't counted): A_w & A_b
Count the number of "missing officers" for each sides (missing queen, or other officers less than the second of that type): M_w & M_b

Then the following elegant "supply & demand" inequalities are necessary and sufficient criteria for a legal collection:
M_b + 2*A_b >= N_w - M_w - A_w
M_w + 2*A_w >= N_b - M_b - A_b

Grouping the terms by White & Black, the left hand side is the "supply", the right hand side is the "demand". The supply is always non-negative, so if the demand is zero or less, it's always satisfied. Similarly, a supply of 8+ will meet any demand that can occur.
Here's an example. Can we have 18 queens on the board? Yes!
N_w = N_b = 8
(because 8 promoted pawns on each side)

A_w = A_b = 0
(every missing pawn was promoted)

M_w = M_b = 6
(all Rs, Bs & Ns were captured)

M_b + 2*A_b >= N_w - M_w - A_w
translates to:
6 + 2*0 >= 8 - 6 - 0
6 >= 2

So this is legal. Similarly for White supply for Black demand. Even if we had the knights still on the board, so M_b = M_w = 4, the inequality would be 4 >= 4, so still legal.
Aside on mate/stalemate
Some wonder if such a position can be achieved without mate or stalemate, which is a fair question. The answer is yes. It's like asking to prove that 450g of cornflakes will all fit in a box. It's a matter of common experience that one can just shake the pack and the cornflakes settle down. There are not too many cornflakes in the box. Although it's obviously illegal, it's possible to arrange the kings and up to 34(!) white queens on the board without mate or stalemate looming. At this density, it getting a bit tight, but this thought experiment shows that when we are dealing with merely 18 queens, where moreover friendly queens can shield against enemy ones, there a vast amount of slack, and no need to worry about forced mates or stalemates. Even with 18 queens, the chessboard is a very empty box of cornflakes :-)
Counting the collections
Let's focus on just the White units first. How many legal White collections are there? 8,694. Here's a quick proof.
Let k be the number of visible promotions to rook, knight or bishop (i.e. officers beyond the original complement of 2 for any of these types). (For symmetry reasons, queens are dealt with in a couple of paragraphs instead.)
Let v(k) be the number of different combinations of R,N,B which achieve this.
v(0) = 27:
because there may be 0-2 remaining of each of R,N,B.

For k>0, v(k) = (k^2 + 15*k + 38)/2
e.g.:

v(1) = again 27:
3 ways to pick one of R,N,B to be 3;
& 0-2 possible for each of the other two types.

v(2) = 36:
27 ways to have 4,0-2,0-2;
& 9 ways to have 3,3,0-2.

Then the other 8-k pawns may still be Ps, or turned into Qs, or captured.
Let q be the number of visible queen promotions (i.e. queens beyond the original complement of 1).
Let u_k(q) be the number of different combinatorial ways we can achieve this (in terms of surviving pawns, queens and captured pawns)
u_k(0) = 2*(9-k)
because we can have 0 to 8-k pawns, and the rest are captured,
independently we have 0 or 1 queen.

For q>0, u_k(q) = (9-k-q)

s(k) = sum(q=0,...,8-k) [u_k(q)]
= 2*(9-k) + (8-k) + (7-k) + ... 1
= (9-k)(12-k)/2.

Check:
s(8) = 2: 0-1Q
s(7) = 5: 0P,0-2Q; 1P;0-1Q
...
s(0) = 54: = 55-1

So the total number of of legal White collections is:
sum(k=0...8) [s(k)*v(k)]
= 8,694

All of these white collections are indeed achievable, e.g. if Black has only bare king remaining, but in fact in many other situations too: the supply/demand inequalities are not very demanding.
The next exercise involves counting for each combination of N_w, M_w ,A_w how many White collections exist.
I computed the following table of numbers of collections, sorted according to the total number of pieces on the board, as shown in this table:

For each number of units from 2-32, this shows

v_0: the number of basic candidates without worrying about supply-demand,
v_1: the number who have a single fail against supply-demand,
v_2:  the number who have a double fail against supply-demand.

To avoid double counting, the number of legal positions is computed as v_1 - 2*v_2 + v_3. My calculations match Kryukov's prior results  exactly.
Note that there are no fails until one reaches 25 units. That's because with 8 captures, all candidate promotion collections can be achieved.
An "extra credit" open question (work in progress)
Retro enthusiasts further distinguish between the colour of squares the bishops are on, since that is an invariant. This has a major, visible impact on potential legality, is part of the essential classification for chess tablebases, and is also an aesthetic concern in composition. The corresponding term then is "non-standard officers" (queens or "tinted" bishops beyond the first; rooks or knights beyond the second). The count of missing officers is based on the same 5 types. The determination of which additional inequalities are necessary and sufficient to characterize legal collections is now substantially more complicated.
The best approach may be to first apply the adapted supply/demand inequalities. Then can ask how many extra pawn captures are required to "nudge" certain bishops to the correct tint?
A pawn capture of an officer/pawn will result in a batch of respectively 2/3 pawns all promoted on same tint squares, but it seems that for each such batch, we are free to choose the tint independently.


Should I practice openings of a famous player if I want to play like them? I have always liked the way Mikhail Tal played and I noticed on chessgames.com, that his most played openings are:

As White:

Sicilian (B46, B43, B82, B32, B40)
Ruy Lopez (C92, C95, C93, C96, C84)
Caro-Kann (B14, B17, B18, B12, B10)
French Defense (C07, C18, C09, C05, C16)
English (A15, A14, A13, A17, A16)

As Black:

Sicilian (B43, B40, B46, B22, B52 )
King's Indian (E94, E92, E98, E69, E62)
Queen's Pawn Game (E10, A46, E00, A40, A41)
English (A15, A14, A13, A10, A17)
Nimzo Indian (E48, E52, E53, E46, E56)
Modern Benoni (A56, A64, A61, A62, A65)

Mikhail Tal is regarded as the best attacking chess player of all time, but are the openings above indicative of his style? Are they openings that are indicative of an agressive, attacking player?

I know there is more to learning that openings, but basically my main question is if a certain player had a style, does playing their openings help you play with their style?

The openings are a good start; they give players like Tal the opportunities for combinatorial wizardry.  But it's a lot to ask of oneself, to play like Mikhail Tal.

They say that Tal played a lot of speculative sacrifices. That is, he felt the sacrifice was sound enough, but he didn't calculate it out to be sure.  Maybe.  Be advised, however, that the man didn't get to be World Champion by guessing.  He could calculate.

Unlike mere mortals, Tal's brain could cash the checks his fingers wrote.

If you want to play like him then develop your tactics specifically where unbalanced positions are concerned, look for opportunities, and don't be afraid to lose.  You'll have to be just as fierce, fearless, and skilled, relative to your peers.

NOTE - remember, what matters is that you win (or lose) the game well.  It does not matter if someone uses some computer to refute your moves after the fact.  The only refutation that matters is the one your opponent finds over the board.


Do the rules of blitz chess allow a draw to be claimed if the position is dead drawn? Consider this objectively drawn position that occurred in the Fischer vs Spassky 1972 match, game 12. Suppose this position occurred in a blitz game where Black barely has few seconds remaining on his clock. Black decides to give up the f5-pawn and instead sit comfortably with his pawns on f6 and h6 as follows-
   [fen "8/5p2/6kp/p4p2/2B5/1P2PK1P/8/4b3 w - - 0 1"]

   1. Kf4 f6. 2. Bd3 Bb4. 3. Bxf5+ Kg7.

This position is an impenetrable fortress. Because of the presence of bishops of opposite color, there is no way White can check the Black king or even try to win a pawn by attacking it. If White marches up the e-pawn, Black can simply capture. There is no way White can win. Black simply has to keep moving his bishop safely on the a5-e1 diagonal.
Now, since this is a blitz game and Black just has a few seconds left, White simply attempts to run Black out of time just by making legal moves without making any kind of progress. In such a scenario, would Black be allowed to pause the clock and claim a draw?

No. There is a rule like that for standard time controls (rule 10.2 under FIDE rules), however under blitz rules 10.2 doesn't apply. Appendix B, rule B.3.b:

b. Article 10.2 and Appendix A.4.c do not apply.

In blitz, the clock is just as much a part of the game as the board is. If you have a position like that with seconds left and your opponent has more, you are lost.


How accurate are chess engine ratings? In light of the ongoing TCEC tournament, I was thinking, how do they come up with the ratings of these computers?
Presumably, a 2000 rated chess engine should expect a score of about .5 against a human rated 2000. This perhaps makes it easy to verify if chess engines are really approximately the rating they say they are. However, this is problematic for higher rated programs like komodo, who is supposedly around 3250. Obviously, no humans play at this level. Furthermore, even 2800 rated computers do not play against humans(I doubt magnus plays against computers to help developers define their rating). It is even suspicious if engines play against grandmasters to determine their strength. So, I suspect that these engine ratings are determined by engines playing opponents of similar strength a long time ago, and most ratings come from engine vs engine games these days. But if this was true, I wouldn't expect that engine ratings are accurate in comparison to the human elo scale. Is there a way that they check that engine ratings are accurate?

Computer chess engine ratings are not related to the FIDE rating list.

For example, the MicroMax engine has around 1950 rating on CCRL:

  http://www.computerchess.org.uk/ccrl/4040/

I distribute an iOS app (ChessMini) for this engine. I wrote on the app description page:

  The engine has a rating of Elo 2000 on the Computer Chess Rating Lists and is stronger than 70% of the human chess players.

This is true only if the CCRL chess rating is a close approximation to the FIDE rating list.

Unfortunately, I've received several users complained that they were able to beat the app convincingly despite their FIDE ratings are much less than 1900. In fact, I have a FIDE rating around 2000 myself but the MicroMax engine has never beaten me. I think it's "real" rating on the FIDE scale is 1300-1400.

Forget about the human rating list, just look at the relative ranking.

Computer chess ratings are extraordinary accurate (but no relationship to FIDE) because the sample size is only bounded by your processing power. You start an engine tournament, leave the computer running and goto bed... It's 24 hours chess like TCEC. You play as many engine matches as your computer can afford.

Computer engines get a rating by playing other engines. No human intervention. No grandmaster. Anybody with a laptop can do that:

Download Arena or Cutechess
Download your favorite engines
Start an engine tournament

That's it, it's so simple! You'll get estimated ratings for your engines.


How can Black free his game? What are Black's long term plans in below pawn structure?
How can Black free his game?

The position arose from the Rubinstein variation of the French defense:

[Title "White to move"]
[fen "r2rb1k1/1p2bppp/1q2pn2/p3B3/P2N4/2PB4/1P2QPPP/R2R2K1 w - - 0 1"]

Hm, my idea is this:

pawn structure should remain as is except pawn should be probably on
g6 preventing king side attacks and giving space to move bishop
Be7-f6-g7
move knight to better position Nf6-d7-c5 and focusing attack on weak
pawn a4 with help of white squared bishop
move black squared bishop to a1-h8 diagonal which will make pressure
on pawn c3 if white b pawn is moving to protect a pawn

It doesn't look as good endgame for black since he has minority on queen side which can quickly turn into passing pawn therefore I believe black should keep pieces.


Is this queen endgame a win or a draw for White? [FEN "6k1/8/4qp1p/7P/6P1/5P2/6K1/Q7 w - - 0 1"]

I am unable to analyze this queen endgame in which it is White's turn. Is it a win or a draw for White?

I analyzed your position with Stockfish 11 ("Stockfish_20011801_x64_modern" to be exact) to a depth of 78 and it returned the following line as the best continuation.
6k1/8/4qp1p/7P/6P1/5P2/6K1/Q7 w - - 0 1

1. Qa8+ Kf7 2. Qb7+ Kg8 3.Qb8+ Kf7 4. Qb1 Qe2+ 5. Kg3 Qe5+ 6. Kf2 Qh2+ 7. Ke3 Qe5+ 8. Qe4 Qc5+ 9. Ke2 Qb5+ 10. Kf2 Qb2+ 11. Kg3 Qa1 12. Qc4+ Ke7 13. Qc7+ Ke6 14. Kg2 Qb2+ 15.Kh3 Qf2 16. Qc4+ Kd6 17. Qe4 Qg1 18. Qb4+ Ke6 19. Qc4+ Ke7 20. Qd3 Qh1+ 21.Kg3 Qa1 22. Qe3+ Kd7 23. Qe4 Qa5 24. Qd3+ Ke6 25. Qe3+ Kd7 26.Kh3 Qb5 27.Qe4 Qf1+ 28. Kg3 Kd6 29. Kf4 Qb5 30. Qd4+ Ke7 31.Qe3+ Kf7 32.Kg3 Qb8+ 33.Qf4 Qb6 34. Qc4+ Kg7 35. Kf4 Qb8+ 36. Ke3 Qa7+ 37. Qd4 Qb7 38.Kf2 Qc7 39.Qb4 Qh2+ 40. Ke3 Qg1+ 41. Ke4 Qa7 42. Qd6 Qa4+ 43. Ke3 Qb3+ 44.Qd3 Qe6+ 45. Kd2 Qa2+ 46. Ke1 Qa1+ 47. Kf2 Qb2+ 48. Kg3 Qb8+ 49. Kg2 Kf7 *

As you can see by playing through the variation, no progress ends up being made and the game one way or another ends up drawn through the 50-move rule (I say one way or another because white theoretically could push say the f pawn at the end of the variation showed and restart the 50-move rule).


What's so important about the h4 square in this endgame? I'm reading John Nunn's book Grandmaster Chess Move by Move, and it stresses the importance of the h4 square in the following endgame.

8/2p2p2/5k1p/2B1p1p1/4P3/1P3P2/2n1K1PP/8 w - - 0 1

1. Kd2? Nd4 2. Bxd4 exd4 3. b4 Ke5 4. Kd3 h5! 5. g3 h4

Nunn writes,

  and [Black] is just in time to prevent h4 by White. Now White cannot make progress and the game is drawn.

Using computer analysis, I see that the move 6. Kc4 loses in the resulting position, due to 6... hxg3 7. hxg3 g4! So white's best attempt is not Kc4 but rather playing f4 at the right time.

Why is it advantageous for each side to occupy h4? I have some thoughts on the matter but would appreciate a more complete answer.

Thoughts:

If white occupies h4, he can exchange hxg5 hxg5 at the right time and liquidate the kingside, so that black can't queen with an h-pawn. This is especially important since white's plan is to push f4, capture the d4 pawn and then attack on the queenside. Better not to leave behind a black h-pawn that can queen.
If black occupies h4, then he has an advanced h-pawn that can
potentially queen, especially if white tries to break through with
f4. (In the case of f4, black can counterattack on the kingside.)

Compare the above (drawn) position with the position below which is won for white. The moves are given by Stockfish. I think this illustrates why exchanging h-pawns is advantageous for white, so that he can attack on the queenside more freely.

8/2p2p2/7p/4k1p1/1P1pP2P/3K1PP1/8/8 w - - 0 1

1. hxg5 hxg5 2. b5 f6 3. f4+ Ke6 4. Kxd4 Kd6 5. e5+ fxe5+ 6. fxe5+ Ke6 7. Kc5 Kxe5 8. Kc6 Ke4 9. Kxc7 Kf3 10. b6 Kxg3 11. b7 Kf2 12. b8=Q g4 13. Kc6 Kg2 14. Kd5 g3 15. Qf8 Kh2 16. Ke4 g2 17. Qf4+ Kg1

What are your thoughts on the endgame? Why do you think the h4 square is important for both sides? Am I leaving something out in my analysis?

Your thoughts are correct.

In pawn endgames with play on both wings, it is often decisive for one side to be able to reduce his pawn majority to a 1 vs 0 situation ; reversively, he wants to ensure he keeps a pawn on the side where he has a pawn minority.

The idea is that the opponent king will be diverted by your eventual passer and take it (thus opening space for your breakthrough or counterplay on the other wing). If you have reduced your majority to a 1 vs 0 situation, there is nothing more for the opponent king to do. Otherwise, it would remain active and grab enough of your pawns on this wing to get a passer of his own.

I am familiar with this concept thanks to an excellent book by Glenn Flear. I haven't seen it in print anywhere else.

That's exactly what happens in your example. White gets a 4 vs 3 majority on the kingside. If he can reduce it by exchanging the h-pawns, he will sac his eventual extra f-pawn to distract the Black king and win on the other side (take Pc7, queen b-pawn).

However, if Black can retain the h-pawns (and if they are not too far north), the black king will be able, after taking the f-pawn, to also collect white h-pawn, and threaten to queen his own h-pawn.

That's why White needs to exchange the h-pawns early (or to ensure they stay far enough up the board for Black's counterplay to be too slow) with h2-h4 and hxg5.

See comments in this line:

8/2p2p2/7p/4k1p1/1P1pP2P/3K1PP1/8/8 w - - 0 1

1. hxg5 hxg5 2. b5 f6 3. f4+ gxf4 (3...Ke6 {loses trivially}) 4.gxf4 Kf4 5.Kd4 {Thanks to zugzwang, White can also exchange the 4 and f6, even if that's not necessary here} Kf3 6.e5 fxe5 7.Kxe5 {And the White King wins Pc7 and the game, while the Black King has nothing to attack anymore and is just out-of-play. Add wPh2/bPh4 and the evaluation changes !}


What is the fastest possible stalemate by castling? It is known what the fastest stalemate is. But what but is the fastest possible stalemate in which castling must be the last move?
33 plies is my best result so far.
[FEN ""]

1. e4 h5 2. Qxh5 d6 3. Qxh8 Bh3 4. Qxg7 Bxg2 5. Qxg8 Bxf1 6. Qxf7+ Kd7 7. Qxf8 Kc6 8. Qxd8 e5 9. Qxd6+ Kb5 10. Qxc7 Bd3 11. Qxb8 Bxc2 12. Qxa8 Bd1 13. Qxa7 Kc4 14. Qxb7 Kd3 15. Nf3 Kc2 16. Qb3+ Kxc1 17. O-O

Castling for a pin isn’t the only possible motivation though. Here is another 33 plies sequence that shows motivation in protecting pieces and guarding squares.
[FEN ""]

1. f4 e5 2. fxe5 d6 3. exd6 Qg5 4. dxc7 Ke7 5. cxb8=Q Qxg2 6. Qxc8 Qxh2 7. Qxa8 Qxg1 8. Qxa7 g5 9. Qxb7+ Ke6 10. Qxf7+ Ke5 11. Qxf8 Qh2 12. Qxg8 Qh5 13. Qxh8+ Kf4 14. Qxh7 Kg4 15. Bg2 Kg3 16. Qxh5 g4 17. O-O

I’ve found a way to reduce the count down to 31 plies.
[FEN ""]

1. f4 e5 2. fxe5 d6 3. exd6 Qg5 dxc7 Qxg2 5. cxb8=Q Qxh2 Qxa7 Qxg1 7. Qxa8 Qg2 8. Bxg2 g5 9. Qxb7 g4 10. Qxc8+ Ke7 11. Qxf8+ Ke6 12. Qxf7+ Ke5 13. Qxg8 Kf4 14. Qxh8 h5 15. Qxh5 Kg3 16. O-O

White has only two non-capturing moves, the first pawn move and casting. Black uses up all of their moves without rest. Therefore, I think that 31 plies may be optimal unless a pawn capture can be shaved off.


What are the ideas behind the Short variation in Advance Caro-Kann? What are the main strategic and tactical ideas behind the so-called Short variation in Advance Caro-Kann? I mean this line:

[FEN ""]
1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nf3 e6 5. Be2

Isn't White's position a bit passive, and furthermore with Black's Bishop already developed in f5? Why do GMs play this line?

Here are a few observations regarding the line:

Replacing the 5th move with 5. Bd3 is a bad move. Black trades bad bishop for good with 5...Bxd3
Unlike the Nunn-Shirov attack (1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nc3 e6 5. g4), White aims to get his King to safety by castling before any fireworks begin. To facilitate this the Bishop has to make way. We've already ruled out moving to d3, a fianchetto would be terribly slow and highlight the weakness of the bishop being restricted by its own pawns, and lastly there are no other safe squares
White knows that Black's pawn break ...c5 will use an extra tempo, and if it comes too soon then White's safe King and lead in development will favour the first player. Often Black will play an ...f6 break instead
Regarding a ...c5 break, White has the option to reinforce the pawn with ...c3, compared to the Nunn-Shirov attack where a knight restricts that advance
Again to restrict the ...c5 break, White will often develop the dark square bishop to e3 to overprotect d4. Black's minor pieces often settle on the following squares: ...Nb8-d7, ...Bf8-g7, ...Ng8-h6(!?)
Black does not fear the bishop taking the h6 knight. The Bishop pair and semi open g-file provide ample compensation for the doubled h-pawns, which are not easy to attack. Often White will have to un-double these pawns for defensive purposes
White often tries to gun down the light square bishop with the f3 knight, to win the 2 bishops. Black often plays ...h5 to gain king side space and give the light square bishop a flight square
Extra: White also plays for the c4 break to dissolve the centre. Black often gives White an isolated Queen's pawn with ...dxc4, which often results in White losing time with the recapture Bxc4. Thus ensues the dynamic contest of White's semi-open files and potential piece play in the middle game compared to Black's solid structure that will favour the second player in the endgame

If you want to know (a lot) more, then check out The Caro-Kann: Move by Move by Cyrus Lakdawala. Also, this chess.com link has a discussion on the line: http://www.chess.com/forum/view/chess-openings/advance-shirov-vs-advance-short-in-the-caro-kann


Notes on Chess Piece Class I have following this tutorial http://www.chessbin.com/post/Chess-Piece-Representation to build simple chess engine right now .

at the very first step of Chess Piece Class there are many things confuse me.

why do we need many values to evaluate a chess piece for example :

pieceValue , pieceActionValue, AttackingValue, DefendingValue.

and is there any standard numerical values for evaluating chess pieces ?

Thanks

Chess engine algorithms are implementation dependent, thus there is no such thing as "standard numerical values". Unfortunately, you will need to come up with your own values. However, you can apply some common sense such as the piece value for a queen must be higher than a rook. If you're confused, please take a look at the TSCP source code. It's a very simple chess engine.

Everything you mention is standard in chess. When you play chess, you do look the attacking/defending pieces, right?

Please take a read on:

https://chessprogramming.wikispaces.com/Evaluation

Modern chess engines such as Stockfish has many more evaluation terms. The difficulty in coding a evaluation function is the main motivation for machine learning (neural networks).


Tactics to counter Queen's Gambit I am a novice player. I have seen many White players using the Queen's Gambit (1. d4, 2. c4) which actually dominates the center and inflicts humongous damage at the expense of only one white pawn. What should be my response towards such a strategy?

You do not have to accept the gambit with 2... dxc4. This is chess, not draughts; capturing is not mandatory. (You know that, but this is a standard reply to gambits and other sacrifices.)

Both 2... e6 (the 'orthodox' Queen's Gambit Declined) and 2... c6 (the Slav) are solid choices, many grandmasters have them in their repertoire. Black's position might be a little cramped in some of the lines that follow, but (s)he'll keep a strong influence in the center.


Why does the Hyper Accelerated Dragon avoid the Rossolimo? After
1. e4 c5 2. Nf3 g6 3. d4 cxd4 4. Nxd4 Nc6

Why is the Rossolimo line impossible for white?

[fen ""]
1. e4 c5 2. Nf3 g6 3. d4 cxd4 4. Nxd4 Nc6

In the Rossolimo proper,

[FEN ""]
[Title "Rossolimo variation"]
[Startply "5"]

1. e4 c5 2. Nf3 Nc6 3. Bb5 g6

white usually holds back pawn to d4 and doubles black pawns with Bxc6, or later builds a center with an eventual c3 followed by d4.

In the Open Sicilian,

[FEN ""]
[Title "Open Sicilian"]
[Startply "9"]

1. e4 c5 2. Nf3 g6 3. d4 cxd4 4. Nxd4 Nc6 5. Bb5?!

none of these plans are available, and 5. Bb5 doesn't make much sense. Besides, the bishop on b5 is tactically vulnerable to a later black Qa5+ or Qb6.


Instead of giving checkmate, I gave stalemate. Why? I am a beginner, and I have just discovered this annoying stalemate. I got the definition but while playing, I ended up with a stalemate and I don't know why. Could you explain it to me?
[FEN "8/8/4K3/8/6R1/2k5/7R/1R1R4 w - - 0 1"]

I had 4 rooks that were supposed to block the king so he could not move anymore. Isn't this supposed to be checkmate?

No; for checkmate, the king must be in check, i.e. attacked by one of your pieces. This isn't the case in the position you posted, but if you were to move, you'd be able to force mate in two:

[FEN "8/8/4K3/8/6R1/2k5/7R/1R1R4 w - - 0 1"]

1. Rh3+ Kc2 2. Rg2#

Actually, you don't need that many rooks to checkmate. A lone king and rook will be enough; the procedure is explained in this Wikipedia article.


Is there a software to measure a player's strength based on a game? I flicked through some papers that described how one can obtain an ELO estimate based on a game. (Basically we were comparing players' moves to the best moves suggested by a strong chess engine.
My question is, is there any online/offline resource when I can do this?

It's a matter of how much data there is. When you first get a rating in a tournament, it is a provisional rating until you reach X number of games. In the US I think you need 20 games. The provisional rating fluctuates more because of a single loss or win.
However, I recently obtained a copy of Houdini Pro 4. In the help contents is this: "Unix inventor and computer chess pioneer, Ken Thompson, has developed an algorithm which allows one to create an Elo rating list out of an arbitrary set of games".
There is also a step-wise process to generate an Elo list. So, perhaps it can not be done based "on a game", but maybe not too many more are needed using Ken's algorithm? Not sure, I never tried using that tool.


What happens should a clock fail during the game? There are a number of ways a clock can fail during a game.

Battery runs out, player pushes button by mistake and resets it,  falls on floor and breaks, kiddie smashes toggle button hard with captured queen and clock stops [I have seen that kiddie type of hitting the clock hard with a piece usually a queen on several occasions], yada yada.

So what happens if in the middle of a game the clock stops working correctly?

This would clearly impact games more that are nearing the end and players are in time pressure,   as well as for speed games where the delay in correcting the problem would have more significance than at the beginning of a long slow OTB game.

Per FIDE rules 6.10a and 6.10b (I am including the latter since it is so closely related in that it can require the arbiter to adjust the times based on judgment):

  6.10 a. Every indication given by the clocks is considered to be conclusive in the absence of any  evident  defect.  A  chess  clock
  with  an  evident  defect  shall  be  replaced.  The  arbiter  shall
  replace  the  clock  and  use  his  best  judgment  when  determining
  the  times to be shown on the replacement chess clocks

  6.10 b. If  during  a  game  it  is  found  that  the  setting  of  either  or  both  clocks  was  incorrect,  either player or the
  arbiter shall stop the clocks immediately. The arbiter shall install
  the  correct  setting  and  adjust  the  times  and  move  counter.
  He  shall  use  his  best  judgement when determining the correct
  settings.

Per USCF rules:

  16 O. Defective clocks. Every indication given by a clock is considered
  to be conclusive in the absence of evident defects. A player who
  wishes to claim any such defect must do so as soon as aware of it. A
  clock with an obvious defect should be replaced, and the time used by
  eachplayer up to that time should be indicated on the new clock as
  accurately as possible. The director should use judgment in
  determining what times shall be shown on the new clock. A director who
  decides to subtract time from one or both players shall leave that
  player(s) with the greater of either five minutes to the time control
  or at least one minute for each move the player still needs to meet
  the time control.

Again, I am going to include this since it is closely related, and is akin to what I posted for FIDE above.

  16 P. Erroneously set clocks.An erroneously set clock should be
  handled in the same fashion as a defective clock. As in 16O, the
  director should use judgment in deciding whether to make time
  adjustments. The most common situation of this type involves an analog
  clock set to expire at 7:00 rather than the correct 6:00. This is best
  handled by pointing out to both players that the time control expires
  at 7:00. Clocks can also be reset for the correct time controls and
  the correct elapsed timefor each player.Sometimes this hour difference
  is not pointed out and there is an eventual time claim. Even though
  the clock may show 6:00 with a flag down, or the signaling device on a
  delay or digital clock indicates a flag fall, if the total elapsed
  timeshown for both players is about an hour more than possible,
  considering when the game started, the player should not be forfeited,
  and should be given the hour in question.