Strategy in Isolated Queen Pawn Positions

First of all, the isolated pawn is a dynamic strength, and a static weakness.

But what does this mean?

This means that he represents a pawn weakness, but compensates this weakness in some other way. In short, Black should strive towards endgame, while White must obtain some sort of pressure/attack in order to compensate for his weak d-pawn.

Why is this so, and can Black/White achieve his plan? This will be the topic of the text below.

Characteristics of the Isolated pawn:

If left alone and unhindered, it will expand and cramp the enemy, yet if blockaded it becomes a target and a bottleneck.

The shortcomings of the isolated pawn are inability to defend it with another pawn and the fact that the square in front of him ( and sometimes the squares around him too ) is weak and can be used as a strong-point for the opponents pieces. This is most evident in the endgame. Aside from that, the benefits of the isolated pawn are seen in the middlegame in view of space advantage,open lines and aggressive strong-points in the center, especially the e5 square.

  What should Black's plan be in Isolated Queen Pawn Openings like this one arising from the Caro-Kann Panov attack?

These plans are typical and well explored. Opening moves just make some plans possible and some not.

Plans for both sides in the position with Isolated pawn:

Here is a short summary of the plans for both sides:

Plans for the side with the isolated pawn :

Attack on the kingside;
Favorable opening of the center;
Advancing the isolated pawn in order to cramp the opponent;
Development of initiative on the queenside;

Plans for the side fighting against the isolated pawn :

Simplification of the game with goal to transpose into favorable endgame;
Transposing into the position with hanging pawns;

In order to help you better grasp these plans here are the illustrative games:

Plan for side with the isolated pawn: Attack on the kingside :

Botvinik-Tolush, Moscow 1965 is a good example for this. The key idea is to push f4!, which gives White the attack. Smyslov-Ribli, London 1983 seventh game is another good example.

Plan for side with the isolated pawn: Favorable opening of the center :

Spassky-Avtonomov, Leningrad 1949 is a good example. Pay attention to White's d5! push, opening lines and activating his pieces.

Plan for side with the isolated pawn: Advancing the isolated pawn in order to cramp the opponent :

Novoteljnov-Bondarevski, Moscow 1951 is one  good example. Pay attention to 12...d4!.

Plan for side with the isolated pawn: Development of initiative on the queenside :

This happens rarely, but I was able to find illustrative game. Notice how Black exploits queenside weaknesses with 16...Qb5 to increase his initiative in the game Bitman-Zlotnik, Moscow 1979. I can not find online resource for this game.

Now after seeing plans for the side with isolated pawn we must examine plans for the side fighting the isolated pawn:

Plan for side fighting the isolated pawn: Simplification of the game with goal to transpose into favorable endgame :

Karpov-Spassky, Montreal 1979 is a very good example.

Plan for side fighting the isolated pawn: Transposing into the position with hanging pawns :

Zukertort-Steinitz, Vienna 1886 is a classical example. Notice how Steinitz exchanged pieces, thus reducing White's attacking potential. As soon as White is not able to attack he starts to stand worse due to the weakness of the isolated pawn.

Furman-Kholmov, Kiev 1954 and Taimanov-Karpov, Moscow 1973 are very good examples of a positional approach. However, you might be forced to destroy hanging pawns dynamically like in Petrosian-Smyslov, Moscow 1961.  Pay attention to 18...Rxc3! strike.

But how does all this apply for your line in Panov attack?

Typical plans in the position with isolated pawn are not opening dependent. Opening moves can only enable some plans and make others impossible to execute, but no matter what opening you play the typical plans remain the same.

This is very important to know. In order to choose proper plan you must know the current opening theory.

I believe that little has changed and that you will have to implement the plan of transforming White isolated pawn into hanging pawns, and then attack them.

You should also cement a piece on d5 and avoid transformation of the current pawn structure, unless it favors you ( hanging pawns as I have said, are the only good pawn structure for you, others favor White ). As said, 4 minor pieces on the board are good for White, 3 is unclear and everything else favors Black.

Just exchange smart and you will be on a good way to at least draw.

The paramount importance is the opening play. If you get good position from opening, then it will be easier for you to play the position as your plans are clear and straightforward. White on the other hand has to generate an attack which is not that easy, and usually will have to be satisfied with a small space advantage.

ILLUSTRATIVE GAMES FROM OP's OPENING:

We shall analyze games #2 and #6 from Kamsky-Karpov, Elista 1996 which will hopefully help you grasp the above mentioned concepts:

First quickly play through the games 2 and 6. You will notice that everything was the same until move 12 where Black first played Bd7 and Rc8, sticking to passive defense, while in the game 6 he played more active Qb6 which allowed him to exchange few pieces.

Notice how in the second game Black was cramped due to the presence of 4 minor pieces on the board and because he had no counterplay. Also pay attention to 45.f4! that launched a kingside attack. This is the topic we covered above under kingside attack. The attack was possible due to the 18.d5! which opens center favorably, again we mentioned that too under favorable opening of the center.

Now look how Black stood much better when he played actively, and when he exchanged a minor piece. Notice how he had more space to maneuver, and notice how he immediately took d5 square, and other ones around the d4 pawn, under his control. This is important! "Cementing" a piece on d5 hinders opponent's attacking potential. Pay really good attention to this. After 23.Bxf5 we can see that White has lost his space advantage, and now Black got fully equal game since only 2 minor pieces were left. Black equalized by keeping the squares around isolated pawn "in check". Also, he had enough space to properly regroup his pieces for defense and counter attack.

Another highly instructive game is J.Polgar-V.Smyslov, Aruba 1992. Just look how Black exchanged the queens with 9...Qb6! and 10...Ba5!and then look how White's isolated pawn became instantly weak when he was not able to attack anymore. Black had pressure in that game in the end but since there were 4 minor pieces White had enough defenders for his weak pawn.

A CONCRETE PLAN SUGGESTION FOR THE OP's POSITION:

I used to play Caro-Kann, so in the position you mention my plan would be:

To finish my development.
Exchange at least one minor piece.
Solve the problem of developing my light-squared bishop, usually by playing b6+Bb7 or by playing Rd8+Bd7+Be8. These are typical maneuvers for Black.

At that point opening ends and starts the middlegame. There you can try to implement one of the 2 above mentioned plans. It all depends from White's moves. Still, you will probably exchange knights on c3 and maybe dark-squared bishops, which will result in the pawn structure with the hanging pawns.

About the move order in your post:

White takes on d5 too early, so all kind of options are possible for you. Still, you have 3 good moves as Black after he plays: Nc6, Bb4, Be7. Personally, I prefer solidity above all, so I would choose Be7 but the best move in my opinion is Bb4.

Again I must stress that it is of paramount importance to leave the opening with equal position. The same goes for White too.

SUMMARY:

For detailed explanation of plans in the Isolated pawn position consult the following books:

I.Sokolov-Winning chess middlegames, Baburin-Winning Pawn Structures and especially B.A.Zlotnik-Typical middlegame positions. The last book is pure gold and is out of print, but still try to find it.

As for Caro-Kann, Panov attack you should get Karpov's book A.Karpov & M.Podgaets-Caro-Kann defense Panov Attack, Batsford 2006. It is entirely devoted to Panov attack, and I think it is outstanding.

Sorry for scarce information, but there is just too much to be said for this topic that it wouldn't fit here. So if you have follow up questions just leave a comment.

Best regards.


Is the Poisoned Pawn variation of the Najdorf (7... Qb6) considered some sort of refutation of 6.Bg5?

The problem with Bg5 is mainly that black will usually be better prepared than white in the messy poisoned pawn. He either doesn't play it or he knows it. On the other hand imagine Be3. There black is quite predictable as not following the main lines is too dangerous. White has a lot of good systems to try so he has much easier life. Objective quality is not that important part of decision process what to play as Be3 Najdorf, Bg5 Najdorf as well as Queen's Indian end virtually always in draw in correspondence games. To me Be3 Najdorf seems so unpractical for black that I would prefer dragon, Sveshnikov or classical over it. Knowing that with white, who would try so hardly to get the Bg5 mess against well prepared opponent?


How does X-FEN (Chess960 FEN) differentiate from traditional FEN notation?

Let's start at the beginning
To understand X-FEN for castling in Chess960, it helps if you first understand castling in Chess960. Castling rules are slightly different in Chess960, hence there comes a need for X-FEN. I believe it's the major source for your confusion.
Minor Note 1 X-FEN is used not just for Chess960 but for many other variants as well (Capablanca chess, Janus chess, Chess480, etc.)
Castling in Chess960
Castling in chess960 is done on two sides: the a-side and the h-side, analogous to queenside and kingside castling respectively. The final positions after castling are the same in Chess960 and in standard chess.
The terms a-side and h-side are used as the initial board configuration is randomized, and what is queenside in normal chess needn't be so in Chess960 (the same applies for kingside.).
Why FEN is insufficient for Chess960
FEN is sufficient for standard chess, as there are only two initial squares for the rooks, on the a-file and the h-file.If a rook from the kingside somehow gets to say, the c-file, there is no question of allowing queenside castling with it as it isn't on the right square. (More on this in an example.)
In chess960, the rooks have many possible initial squares. In the course of a game, both the rooks could end up on the same side of the king. Now, if FEN is used, there is no way of clearly knowing which rook has the castling rights (without knowing the initial position) as either could be occupying the legal square for castling. As a matter of fact, X-FEN assumes by default the outermost rook in such cases to have the castling rights, but that needn't be the case always.
An example to make my point clear

Standard Chess
If the above position occurred in a standard chess game, the FEN would simply be

rn2k1r1/ppp1pp1p/3p2p1/5bn1/P7/2N2B2/1PPPPP2/2BNK1RR w Kq - 4 11

This is because White can castle legally on the kingside, with the rook on the h-file. The rook on the g-file would play no role in castling, simply because that isn't on the legal square for kingside castling.
Likewise, Black can castle only on the queenside, hence the FEN has a q for the castling rights of Black. The rook on g8 is irrelevant.
Minor Note 2 Precise readers might point out that the number of moves and half-moves required to arrive at the position shown, in a normal chess game, might not tally with the values given in the FEN. That is quite possibly true, but I stuck to the value given for the Chess960 game (for the same position) on Wikipedia, for simplicity's sake.
Chess960
The situation changes if the game is Chess960, simply because the legal initial square for the white rook could be either g1 or h1. We cannot be sure without knowing the initial position. We cannot ascertain which rook has the kingside castling rights.
If the FEN given above was used here, it would confer the castling rights on the rook on the h-file, as the outermost rook is assumed to be the one with the castling rights, by default. It would also mean that Black can castle only on the a-side (queenside, in other words).
As a matter of fact, the initial position for this game was actually

rnbnkqrb/pppppppp/8/8/8/8/PPPPPPPP/RNBNKQRB w KQkq -

If you notice the bold R's, you'll see that the legal square for the white  kingside rook (the one involved in h-side castling) is actually g1, not h1. Similarly, the home square of the black 'kingside' rook is g8, not h8.
This means that using normal FEN not only confers the castling rights to the wrong white rook, it also fails to indicate the ability of Black to castle kingside. It's because normal FEN assumes the initial squares of the rooks to be on the a- and h-files only.
Hence, to avoid the ambiguity caused by normal FEN, X-FEN records the position as

rn2k1r1/ppp1pp1p/3p2p1/5bn1/P7/2N2B2/1PPPPP2/2BNK1RR w Gkq - 4 11

The G (in bold) shows that the castling rights on the kingside are with the rook on the g-file, not with that on the h-file. This is the inner rook. Similarly, it ensures that Black's castling rights on the kingside aren't ignored.
The queenside castling possibility for Black is recorded normally as there is no ambiguity.
Summary
Recording castling in Chess960 using X-FEN works as follows:

Just like normal FEN, if the two rooks are on the opposite sides of the king.

Still like normal FEN, if both rooks are on the same side of the king, with the outermost rook having the right to castle.

Using the letter (capital for White, small for Black) of the file of the rook permitted to castle, when both rooks are on the same side of the king, with the innermost rook having the right to castle. In the above example, G is used to indicate that the inner rook of White (on the g-file) has the right to castle.

Hope that's clear, feel free to ask if there's any confusion!
Note: Special case
In the unusual scenario of three or more rooks (due to underpromotion) being on the same side of the king, with the king yet to castle, there would be an outermost rook, an innermost rook and one or more rooks in between. In such a case, the outermost rook is treated the same way as above, and any other inner rook is identified by its file (depending on which has the right to castle).

For the curious, here's the PGN of the entire example game.
[Event "SmirfGUI Computerchess Game"] [Site "CHESSBOX"] [Date "2005.06.19"] [Time "10:22:29"] [Round "Test"] [White "White"] [Black "Black"] [Result "*"] [Annotator "R. Scharnagl"] [SetUp "1"] [FEN "rnbnkqrb/pppppppp/8/8/8/8/PPPPPPPP/RNBNKQRB w KQkq - 0 1"] 1. h4 g6 2. g3 Bf6 3. a4 Qh6 4. Ra3 Bxh4 5. gxh4 Qxh4 6. Qh3 Qxh3 7. Rxh3 Ne6 8. Bf3 d6 9. Nbc3 Ng5 10. Rhh1 Bf5 11. O-O *

Image and PGN courtesy Wikipedia


endgame with single Bishop or single Knight?

If given the choice should I opt for an endgame with a single Bishop or a single Knight?

In order to properly answer this question I must point out differences between bishop and knight:

Bishop is a faster piece and has a longer range of fire, but can cover only half of the board.
Knight on the other hand, is a slow and clumsy piece but covers squares of both colors. When I say clumsy, I am referring about knight's difficulty to position himself fast to the nearby square. Another problem with the knight is that he can not make a move and keep previous square under control which disables him from making zugzwang. For examples of what I have stated here please read my answer to this question. I believe those diagrams demonstrated well my statements.

I will quote highly instructive excerpt from the book Steve Mayer-Bishop versus Knight the Verdict ( but this regards superiority of bishop pair over 2 knights/ knight+bishop ) :

In contrast to the far-reaching bishop, which can become effective from distance, the knight, in order to become effective, has to operate in close proximity to the opposing forces. In order to become lastingly effective, it must find protected squares near the enemy's camp, mostly squares protected by pawns, in asmuch as other pieces are in the long run not suitable for the protection of the knight. It follows therefore that in completely open positions without pawns, the bishop is superior to the knight, a fact that is confirmed by the results of the endgame theory. Conversely, the knight is superior to the bishop in closed positions, on the one hand because the pawns are in the bishop's way, and on the other hand because the pawns form points of support for the knight, as remarked above.

Now is the time to address the actual questions:

  Please consider the below possibilities (with Kings naturally always present and a couple
  of pawns in each case):

  Bishop -vs- Knight
  Bishop and Knight -vs- two Knights
  Rook and Bishop -vs- Rook and Knight
  Queen and Bishop -vs- Queen and Knight

1. Bishop -vs- Knight

As stated above, pawn structure and king's position has a paramount importance.

If there are pawns on both sides of the board and position is relatively open then bishop is usually the better choice. This is especially true if both sides can make a passed pawn since bishop can use his speed and long range to stop/slow down opposing passed pawn while helping his own to advance. Furthermore, if the position is open bishop/king can easily harass the knight forcing him to abandon the control of the key squares due to his short range.

Since this will be a long post let us take a break and enjoy in following demonstration of bishop's superiority in open positions with pawns on both sides:

[StartFlipped "0"]
[White "Stoltz"]
[Black "Kashdan"]
[Event "Hague Olympiad,1928"]
[fen "6k1/p2b1ppp/8/8/3N4/1P5P/5PP1/6K1 b - - 0 1"]

1...Kf8 2.Kf1 Ke7 3.Ke2 Kd6 4.Kd3 Kd5 5.h4 Bc8! 6.Nf3 Ba6+ 7.Kc3 h6 8.Nd4 g6 9.Nc2 Ke4 10.Ne3 f5! 11.Kd2 f4 12.Ng4 h5! 13.Nf6+ Kf5 14.Nd7 Bc8 15.Nf8 g5 16.g3 gxh4 17.gxh4 Kg4 18.Ng6 Bf5 19.Ne7 Be6 20.b4 Kxh4 21.Kd3 Kg4 22.Ke4 h4 23.Nc6 Bf5+! 24.Kd5 f3!-+ 25.b5 h3 26.Nxa7 h2 27.b6 h1=Q 0-1

Notice how Black used his bishop to create zugzwang with 5...Bc8!. That is something knight can not do->bishop moved to c8 and kept f5 square under control. This resulted in White king being forced to allow opposing king to penetrate. This is usual motif in this type of ending. Side with the bishop uses zugzwang to penetrate with the king. Next, notice how Black played 7...h6, 8...g6 and 10.f5! to undermine knight's position. This game well illustrates what quotes from Steve Mayer's book about knight needing stable pawn support in order to be permanently effective. Finally, notice how knight was too slow to position himself properly for stopping the passed pawn after 13.Nf6+.

Here is an example of bishop overpowering knight when both sides have passed pawns and position is open:

[Title "Liverpool-Glasgow, correspondence"]
[fen "8/2n5/5k1p/P1p4P/4K1B1/8/8/8 w - - 0 1"]

1.Be2 Ke6 2.Bc4+! Kd6 3.Kf5 Nd5 4.Kg6 Ne3 5.Be2 c4 6.Kxh6 c3 7.Bd3 Ng4+ ( 7...c2 8.Bxc2 Nxc2 9.Kg6 Nd4 10.Kf6! Ne6 11.a6!+- ) 8.Kg5 Ne5 9.Bc2 Nc4 10.a6 1-0

An important weapon when fighting with bishop against the knight is "domination" and is demonstrated below:

[Title "Bishop dominates the knight"]
[fen "K1k5/8/8/8/2B5/8/8/2n5 w - - 0 1"]

Here is another example where bishop overpowers the knight when pawns are on both wings using "domination":

[White "Goldberg"]
[Black "Tolush"]
[Event "Moscow, 1949"]
[fen "8/pk3p1B/1p1p1P2/2pP2p1/2n5/P1P3P1/7P/4K3 w - - 0 1"]

1.h4! gxh4 2.gxh4 Ne5 3.Bf5! Nf3+ 4.Kf2 Nxh4 5.Be4!+- Kc7 6.Kg3 Ng6 7.Bxg6 fxg6 8.f7 1-0

In open games with pawns on both sides bishop is almost always to be preferred than a knight. This is the case with 90% of endgames. I know others will disagree, but I state this based on my experience and experience from analyzing grandmaster games: Always prefer bishop than a knight in the endgame. Why? Knight is better than a bishop only if the side with the bishop has severe defects in its position and no counterplay whatsoever. I have never seen practical position from a grandmaster game where knight dominated the bishop after both sides played reasonably well. As stated in the quote above from Steve Mayer's book, knight needs secure strongpoint and must be in close proximity of the opponent in order to be efficient. Also, the oposing bishop must be restricted which requires a lot of pawns on the board which is not characteristic for the endgame. To prove my point I am choosing an example where side with the "bad bishop" and isolated pawn manages to hold a draw:

[White "Flohr"]
[Black "Capablanca"]
[Event "Moscow, 1935"]
[fen "8/1p2kppp/p3b3/3p4/3N4/4P3/PP3PPP/2K5 w - - 0 1"]

1.Kd2 Kd6 2.Kc3 b6 3.f4 Bd7 4.Nf3 f6 5.Kd4 a5 6.Nd2 Bc8 7.Nb1 Be6 8.Nc3 Kc6 9.a3 h6 10.g3 h5 11.b4 axb4 12.axb4 Kd6 13.b5 g6 14.Na4 Kc7 15.Nc3 Kd6 16.f5 gxf5 17.Ne2 Bd7 18.Nf4 Be8 19.Nxd5 Bxb5 20.Nxb6 Bc6 21.Nc4+ Ke6 22.Nb2 Bb5 23.Nd1 Be2 24.Nf2 Bf1 25.Nd3 Bxd3 26.Kxd3 Ke5 27.Ke2 Ke4 28.h3 Kd5 29.Kf3 Ke5 1/2-1/2

This endgame has been heavily analyzed and the last time I checked the verdict was it is a draw. Here White had an advantage and still was unable to win. He had better king, better minor piece and better pawn structure. Still, knight was unable to outmaneuver the bishop because he is slower and "clumsier".

2. Bishop and Knight -vs- two Knights

You need to know rules of the knight endings in order to make the right decision. In a nutshell the side with space advantage usually wins.

The principle in endings with two minor pieces is to exchange opponents most active piece, thus transposing into the favorable endgame. Stronger side avoids pawn exchanges, weaker side strives towards pawn exchanges.

3. Rook and Bishop -vs- Rook and Knight

Heavily favored for the side with the bishop. If you can keep both rooks or both bishops it becomes nearly decisive advantage. For practical example look at Fischer-Tal,Curacao 1962. There are more examples from Fischer's games like Fischer-Petrosian,Candidates match 1971 or Fischer-Taimanov,Candidates Match 1971. Although there were 2 rooks and a bishop it is still good example of how you should play this ending.

4. Queen and Bishop -vs- Queen and Knight

Generally speaking, the advantage goes to the side that can attack opposing king. In practice, side with the knight usually has the advantage. Knight's ability to attack squares of both color is more important here than bishop's speed since queen is so powerful that it can both defend and attack thus giving knight enough time to position itself offensively. Still, I must repeat that all depends on a position and ability to attack opponents king.

If you have questions leave a comment.

Best regards.


Is Behting Study Still Beating Computers?

For the record, the soundness of the Behting study has been under a cloud for some time because it is not easy to refute 1 Ng7+ Kg5 2 Nf3+ Kg4 3 Kf5 h3 4 Ke4 g1Q 5 Nxh6+ Kh5 6 Nxg1 h2 7 Nf3 h1Q 8 Nf5 "etc.", but according to recent analysis by GM John Nunn (2012) the study is sound after all.

It should be feasible for a chess engine to reach a 0.00 evaluation because there are only a few thousand drawing positions that need to be evaluated (depending on wK/bQ position, with or without the c/d pawns), and once the search has exhausted that space they'll all evaluate to a draw.

Here's a similar challenge:

[Title "NDE 1986 (2nd Prize, Israel Ring 1986)"]
[fen "5k2/1n6/1p3K2/P7/1P2N3/p1P2B2/8/2b5 w - - 0 0"]

White to move and draw.

Solution:

   1 a6 a2 2 axb7 Bf4 3 Ng5! Bb8! (a1Q 4 Ne6+ Kg8! 5 Nxf4 Qxc3+ 6 Kf5 and Black can't win; 3 . . . Bd6 4 Ne6+ Kg8 5 Nc7! Bxc7 6 Bc4+ draws.  So the Bishop crosses the critical square c7, which however White can exploit too:) 4 Nh7+! Ke8 5 Bc6+ Kd8 6 Ng5 Kc7 7 b5! a1Q (Kd6!? 8 Ne4+ Kc7 9 Ng5 repeating) 8 Nf7! positional draw.


How can I get a collection of chess games with a 'Greek gift' sacrifice?

Something which might help here is Chess Query Language. Just like SQL does for relational databases, CQL can search in a database of chess games for positions/games which match certain criteria.

I must say I have never used it myself, but it seems to be capable of amazing things, far more complex than what you're looking for. Here is an old article showing a few beautiful studies Tim Krabbé was able to find with the help of CQL.


Which international tournament chess game has the record of longest sequence of forced moves until checkmate?

Alekhine - Yates
http://www.chessgames.com/perl/chessgame?gid=1012179

19 moves.  Alekhine resigned a couple of moves before mate.


How many such positions are there? (chess/math checkmate puzzle)

Your second basic position allows for 4 more variants beyond those you already gave, indicated by the following diagram:

[FEN "1q6/1q6/1q6/1q6/Q7/K7/8/1k6 w - - 0 1"]

That brings the tally for "basic positions" to 25. Whether that addition makes the list exhaustive or not I'm not completely sure (though I think it does).

In any case, whatever the number of basic positions is, your extrapolation of the total number of positions from there (x2 for the color switch and x8 for transformations of the board) is correct since the symmetry group of the chessboard does indeed have order 8, as confirmed on p.334 of this chapter from the Handbook of Constraint Programming, for instance. (One does need to be careful about overcounting here, though; see below.) So at the moment I'd conjecture that the answer is 25 x 16 = 400.

I'm adding this mathematical digression because I see from your profile that you're interested in pursuing a further study of math. I may not be saying anything here that you aren't already aware of, but here goes anyway.

Note that there are some chess positions which will come out identical under different symmetries of the board. For instance, consider the act of reflecting across the a1-h8 diagonal. That symmetry of the board will generally change a given position, e.g.

becomes

But of course some positions (namely those that only have pieces on the a1-h8 diagonal) don't change under that symmetry, e.g. the position

remains unchanged when we reflect across that diagonal.

Because of this sort of behavior, one generally needs to be careful not to overcount in this kind of counting problem. For your problem, that means being sure that none of your basic positions repeats itself under any of the (non-identity) symmetries, so that our "x 16" when obtaining the total number of positions from the number of basic positions isn't overcounting. In the present case, your basic positions are complicated/asymmetric enough that it's intuitively clear none of them will get repeated under these symmetries, so there's nothing to worry about, but in math it's often when things are "intuitively clear" that one needs to be most worried about mistakes. (In fact, there's a saying that if you want to find errors in a mathematical proof, start with anywhere it says, "It is clear that ...")


How many different knight's tours are there?

Wikipedia
quotes several sources for a count of 26,534,728,821,064 for the number
of closed directed tours of the 8x8 board.  As Brian Towers notes
in his answer, that is equivalent to the count of Knight's tours
starting from some given square (such as a1) and ending on the same square.
The same Wikipedia page exhibits several such tours.


I do not know if this term is used in other countries, but in the U.S., a “tornado” is a swiss chess tournament with four rounds in one day, typically at a sudden death in 60 minutes time control. It was probably given that nickname because your mind is spinning from so much chess in one day.

I played in the “Queen City Tornado” yesterday, and there were rounds at 10 a.m., 1 p.m., 3:30 p.m., and 6 p.m.. It makes for a very long day.


Is this the position from TCEC Season 18, Game 80 a win or a draw?

The key point in this endgame is that the bishops are of opposite colours. It is a trivial draw. White is a pawn up but with nothing more than barely competent play by black, white will never be able to advance his pawns. The black king can never be moved from b7 and the black bishop can take station on the diagonal between c6 and h1 making the pawn move c6 impossible. Black will also play h5 at some stage leaving him with only the g6 pawn to protect. The f6 pawn is an irrelevance.
To be able to win an opposite coloured bishop endgame one player has to have two passed pawns separated by a minimum number of files. That isn't the case here. The problem for the side with the extra pawns is that the opposing king and bishop can always blockade the colour of the bishop and the attacking bishop cannot help.


How to play against an engine using scid for a particular level?

Manage your engines in Tools.

Select your engine in Play.

Configure the engine, then select your skill level.


How to weakly solve Tiger Hunt, Atlantis Chess and Peasants' Revolt

Even without a computer one can prove that
"Tiger Hunt" (a.k.a. Maharajah Chess) is a forced win.
Certainly the "tiger" can't hope for more than a draw
if White starts with 1 Na3 and then repeats with say
Nf3-g1-f3-... ad infinitum.  But in fact the "tiger"
can be gradually corralled as BlindKungFuMaster suggests;
for instance:

[Title "Tiger Hunt"]
[fen "4q3/8/8/8/8/8/PPPPPPPP/RNB1KBNR w - - 0 0"]

1.Na3 null
2.c3 null
3.d3 null
4.Nf3 null
5.g3 null
6.Bg2 null
7.h3 null
8.Rh2 null
9.Nd2 null
10.Ndc4 null
11.Be3 null
12.Bd4 null
13.b3 null
14.Nc2 null
15.Nb4 null
16.Nd5 null
17.Nf4 null
18.Bd5 null
19.Rg2 null
20.f3 null
21.h4 null
22.Kd2 null
23.Kc2 null
24.a3 null
25.a4 null
26.e3 null
27.e4 null
28.Re1 null
29.Re3 null
30.Be5 null
31.Ne6 null
32.Rge2 null
33.d4 null
34.Nd6 null
35.Kd2 null
36.Re1 null
37.Rh1 null
38.g4 null
39.h5 null
40.g5 null
41.f4 null
42.h6 null
43.f5 null
44.g6 null
45.h7 null
46.Ree1 null
47.Ra1 null
48.b4 null
49.a5 null
50.b5 null
51.c4 null
52.a6 null
53.c5 null
54.b6 null
55.a7 Qe7

The tiger is now limited to the squares d7 and e7.  White can now finish
immediately by Zugzwang (56 f6 or 56 c6 respectively) or continue in
the same fashion:

[Title "Tiger suffocates"]
[fen "8/P3q2P/1P1NN1P1/2PBBP2/3PP3/8/3K4/R6R w - - 0 55"]

1.Ra6 null
2.c6 null
3.Rh6 null
4.f6

and the tiger is completely out of squares (NB there are no legal moves from
d7/e7 to a8 or h8), QEF.


Because black can play 12...Nd4 instead. The threat is to catch the bishop b5 with ...a6 and ...b5 and eventually ...c4. I do not see how white can prevent this. White loses a piece.


Is there an origin or story of where the pieces that make a chess game got their name from?

I believe that the chess pieces are supposed to constitute an army - I'll try to give a breakdown of how each individual name evolved.

Xianqi, or Chinese Chess, originally developed in India before spreading across the world. Xianqi is the Chinese interpretation of the ancient game, and the pieces do really sound like those that would be in an army - General, Advisor, Cannon, Elephant, Horses, Soldiers, and Chariots.

When the game moved to Persia, as referenced by user Akavall in the comments, the Persian word for chariot is "rokh" and is naturally what the piece is called today.

The modern interpretation of chess holds its roots in Spain where one of the final transformations occurred. The General piece became the King and the Advisor became the Queen, as these positions were more familiar in the Western environment. The horses became knights and the elephant became a bishop (I suppose this was influenced by the Church's power during this era). The Soldiers became known as pawns (from Anglo-French poun, or Old French peon).

If you want to read more about this, this link might do a better job explaining it than I did: How Did Chess Pieces Get Their Names?


What positional play strategy should white adopt when fighting against the Philidor exchange variation?

Why not follow that game? - he got a nice centralised position with pressure on d6. No need to take risks with "Ultra-aggressive" moves.


The Indian theme appeared in a game between Rudolf Spielmann and Siegbert Tarrasch (San Sebastián, 1912):

[FEN "..."]
[Event "San Sebastian"]
[Site "San Sebastian ESP"]
[Date "1912.03.12"]
[EventDate "1912.02.19"]
[Round "17"]
[Result "0-1"]
[White "Rudolf Spielmann"]
[Black "Siegbert Tarrasch"]
[ECO "C80"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "82"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Nxe4 6. d4 b5
7. Bb3 d5 8. a4 Nxd4 9. Nxd4 exd4 10. Nc3 Nxc3 11. bxc3 c5
12. axb5 Be7 13. Qf3 Be6 14. Rxa6 O-O 15. cxd4 c4 16. Ba2 Rxa6
17. bxa6 Qa5 18. Bb1 c3 19. Qg3 Rc8 20. f4 Bf5 21. Re1 Bf6
22. Kh1 h6 23. h3 Rb8 24. Be3 Qxa6 25. Rd1 Qa1 26. Qe1 Be4
27. Kh2 Be7 28. Qf1 f5 29. Re1 Bh4 30. g3 Be7 31. Bf2 Bd6
32. Rc1 Kh7 33. Re1 Rb6 34. Rc1 Ba3 35. Re1 Qb2 36. Qe2 Rb4
37. Rg1 Rb6 38. Re1 Qb5 39. Qh5 Qxb1 40. Rxb1 Rxb1 41. g4 Bc1
0-1

I copy Tarrasch's comments to move 41...Bc1 from here and the original source is Tarrasch's book The Game of Chess (London, 1935), p. 422-423.

  "The move Bc1 is analogous to the blocking move of the 'Indian Problem'; intrinsically it is an extraordinarily unlikely, even ugly move, since the Rook which is to give mate is masked. The 'Indian' character of the move is seen in the following variation: 42. Kg1 Be3+! 43. Kh2 Bxf4+ 44. Bg3 Th1#. Another possibility is 42. Be1 Bxf4+ 43. Kg1 Bg3! followed by mate or the gain of the Queen. The main variation is 42. Kg3 g6 43. Qh4 Bxf4+! 44. Kxf4 g5+, and Black wins."


Why is taking the e4 Pawn considered risky here?

Sorry for the lack of a board here, I will learn how to paste boards here soon.

8.f4 b4 9.Na4 (Nce2 is reasonable too) Nxe4, one might ask, what has white got?

O-O and black has serious issues developing as the amazing line given by the comp (I wouldnt have seen this line) :

10...Be7 11. f5 e5 12.Bxf7+! Kxf7 13.Ne6 Kg8 ( Qd7 14.Qg4 wins material back, Bxe6 fxe6 Kxe6 Qg4+ is no good, Ke8 Qd5 wins material back with decisive effect.)

14.Qd5 and Qh5 g6 (h6 Kh7 Qf5- Qxe4 wins) Qf3 win back material.

The safest line that black can go for is 10..Nf6 imo, just retreating, but white has interesting play with 10.O-O Nf6 Qf3 d5 (what else?) 12.f5 (full throttle) e5 (what else?) 13.Re1 or 13.Bg5!? are interesting for white.

The lines go on and on, but white has very direct, brutal play with the pieces working with the f-pawn in some shape or form. Whether it works or not is another matter.

After all, f4 isnt the main line, O-O is. Diagrams below are me visualizing my lines stated above.

[FEN ""]
1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bc4 e6 7.Bb3 b5 8.f4?! b4 9.Na4 Nxe4 10. O-O Be7 11. f5 e5 12.Bxf7+! Kxf7 13.Ne6 Bxe6 14.fxe6 Kg8 15.Qd5

[FEN ""]
1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bc4 e6 7.Bb3 b5 8.f4?! b4 9.Na4 Nxe4 10. O-O Nf6 11.Qf3 d5 12.f5 e5 13.Re1 e4!?

It's probably better it opt for something safe.


Making my own chess studies (like Lichess) with SCID vs PC

Use a separate database per opening, book, or any topic you study. You can export that database later as a single PGN if you want. Imagine what happens if you don't do that: You have to store these games somewhere, right? And you really don't want those in your main database with normal games.
You can also copy games between databases, which is useful if you want to annotate a game and move it back to the main DB later. Don't worry about performance: A database doesn't take any resources (besides disc space) if you don't have it open.
As a bonus, and something that lichess doesn't offer: you can have as many "chapters" (games) as you want, and you can sort them, search for specific positions or comments, whatever you need.


Is there a good example of a paper chess book converted to an ebook?

It depends on what you mean by an "electronic device", but there has been ebook versions of chess books for quite some time, from publishers like Everyman, although admittedly these are nothing like regular ebooks. Of course your device must be capable of running CB reader or an equivalent that can open the chessbase format files.
On the more practical side of things, chess books don't sell very well and formatting even the printed copy is a lot of work. QualityChess has no intention of producing ebooks that can be easily copied:

Q: Will your books be available as pgn or ChessBase e-books?
A: As long as it is easy to copy these forms of readers, it makes absolutely no sense. Why other companies choose to do this is a mystery.


How to see average game length for specific chess opening (number of moves)?

Chessbase has a function "Opening Report" which gives average lenght of White wins/Black wins/draws
Just setup che base position on the chessboard and right-click it


How to be more aware of smothered mate opportunities?

There's a variety of mates that could be called smothered mate, but for what I'd call the "standard" one (sometimes called Philidor's Legacy), like the one in your example, notable signs are (with white mating black as an example):

The black king is in the h8 corner (maybe it just moved there after being checked by the white queen).
The white queen and knight control f7.
The f7 pawn is typically absent but g7 and h7 are still there (g7 and h7 could also be pieces, as long as they don't cover f7 or g8).
The white queen is on the a2-g8 diagonal.
There's a black rook on the 8th rank to do the smothering. (It wouldn't work with the black queen!)

This can be generalized to long castling, but it is less frequent.

Some tactical trainers (or books!) let you practice tactics by theme. I don't know anything about Chessacademy, but one example I know is the tactics in chess.com which has this feature and has a "smothered mate" category (but they use the term loosely!). Maybe after seeing many smothered mates in a row your recognition of them will become more automatic.


Do people who handle blindfolded chess play at reasonably the same strength given enough time to think?

In my experience and opinion

Having more time is not really an advantage when playing blindfold
You have a clearly higher risk of blundering when playing blindfold

Let me try to expand on this.

Playing blindfold in a single game for more than an hour for the entire game is a huge effort of concentration. Playing blindfold for two or more hours on a single game might be too much to handle, unless you have some special method or extreme stamina. So having more time isn't great from the stamina point of view.
There is a clear risk of losing track of something (e.g. a pawn) on the board or forgetting to register one of the moves and later pay for this mistake. The risk for blundering is clearly higher when you don't see the board and the pieces.

My conclusion is that you will definitely play below your full strength. How much below, depends on how well trained you are in playing blindfold chess. If you play on two or more boards simultaneously, I predict that your strength drops even more. My guess is that you can come up to 80% of your full strength when playing blindfold (after a lot of training and practice). Even then, your risk of blundering will be higher!


Exchanging on d5 in queen's gambit like openings

Your incomprehension is very understandable. Black opens with d5 and e6 entombing the light squared bishop only for white to play cd allowing the reply ed from black and, hey presto! the bishop is free! Is white really so stupid? What's the trick?
Well, some white players want the structure that arises, the so called "Carlsbad structure" and they want to pursue the "minority attack".
Here is the pawn structure:
[fen "8/pp3ppp/2p5/3p4/3P4/4P3/PP3PPP/8 w - - 0 1"]

The basic idea is that white will advance the a and b pawns and exchange them for black's a and b pawns leaving a weak backward c pawn and a hole on c5 where white can park a piece. The long term aim is to win this weak pawn and end up in a winning ending a pawn up. QED
Of course life isn't that simple. Nevertheless the minority attack is a template which strong players (over 2000) should know. It can occur in a number of openings, not just the QGD. For instance it also occurs, with colours reversed, in the Caro Kann.
There is actually an English GM, Keith Arkell, who has this as one of his main weapons. He is an expert in the kind of endgames which can arise from this opening and the endgame is where he applies most of his effort. (He is also probably the leading expert on the KRB vs KR endgame. Although a theoretical draw he has won something like 95% of the games where he has had the extra bishop.)
He has just published a book, "Arkell's Endings", which describes his chess philosophy and gives a lot of annotated games showing his methods. The main English chess magazine just published an extract dealing with this topic and including a game. The full article is about half way through this pdf.
Here are some of Arkell's comments and the game:

I rarely look to create unfathomable complications, I don’t carry around an armoury of opening traps, and I don’t concern myself with trying to force a win from the earliest stages. Instead, my opening repertoire and subsequent play are all about creating a framework from which I can try to acquire the tiniest of advantages, and then, inch by inch, convert that into something tangible. Unsurprisingly, I win many of my games in the ending. Very often I am not sure at what point my opponent’s position has deteriorated from what was difficult but tenable, to a forced loss.

Here is the game where Arkell demonstrates his use of the Carlsbad structure as a framework from which he extracts a win.
[Title "Arkell - Bradbury, EACU Open, Newmarket 2019, QGD"]
[fen ""]

1. Nf3 Nf6 2. c4 e6 3. Nc3 d5 4. cxd5 exd5 5. d4 c6 6. Bg5 Bf5 7. e3 Nbd7 8. Bd3 Bxd3 9. Qxd3 {Theory dismisses this position as about equal, or at best only very slightly better for White, but my familiarity with the arising structures gives me a good chance to gain the upper hand} 9...Be7 10. O-O h6 {Normally Black would castle here, but now, by capturing on f6, I would be able to follow up with either 12 Ne5 or 12 b4} 11. Bxf6 Nxf6 12. Ne5 O-O 13. Qf5 {This doesn’t look very ambitious, but I am playing for an endgame in which I can probe on the queenside without having to worry about counterplay} 13...Qc8 14. Qxc8 Raxc8 {My opponent doesn’t make any serious mistakes in this game, but this felt like a minor one since the action will most likely take place on the a-, b- and c-files, so the other recapture was likely preferable.} 15. Rfc1 Bd6 16. Nd3 Rfe8 17. b4 Nd7 { I had calculated 17...Ne4 18. Nxe4 dxe4 19. Nc5 b6 (or 19...Bxc5 20. Rxc5 when b4-b5 will follow, with overwhelming positional pressure) 20 Na6 with the plan of attacking Black’s c-pawn.} 18. a4 {I wasn’t sure about the consequences of 18. b5 c5 19. Nxd5 cxd4 20. exd4 Rxc1 21. Rxc1 and then something like 21...Re2. I’m a pawn up, but it all looks a bit loose, so instead I formulated a plan to fix c6 as a longterm weakness.} 18...Nb6 19. a5 Nc4 20. b5 {Threatening to undermine Black’s whole queenside with a5-a6, so more or less forcing the following sequence} 20...a6 21. bxa6 bxa6 22. Na4 Rb8 {22...Nxa5 23 Nac5 just plays into my hands.} 23. Nac5 Rb5 24. Nxa6 Ra8 25. Nac5 Raxa5 26. Rxa5 Nxa5 {And so we have arrived at base camp – the successful conclusion of the minority attack. I have one pawn island against two; Black has active pieces, so a direct assault against c6 is obviously impossible. The correct procedure therefore is to probe on the kingside in order to inflict a second weakness, or at least to gain some space over there.} 27. g4 { This is by far the best pawn move. If 27 h4 h5 it will be hard to make progress, as breaks with e3-e4 or g2-g4 will involve ruining my own pawn structure} 27...Nc4 28. Kg2 Kf8 29. h4 Ke7 30. h5 { Not only does this move fix a target on g7, but experience of playing these kinds of positions, literally hundreds of times, has taught me that there are certain mating nets Black needs to be wary of.} 30...Nb2 {I felt this was a little impatient, enabling me to activate my rook. It was better to sit tight and await events.} 31. Ra1 Nxd3 32. Ra7+ Kf6 33. Nxd3 Rb3 34. Ne1 Rb6 { Neil played this quite quickly, but I wasn’t sure whether he should be playing 34...c5 instead. Actually I had a similar game at Harrogate about four months earlier where I managed to win from the structure which would have arisen after ...c5.} 35. Nf3 Bb8 36. Rd7 Ke6 37. Rd8 {My opponent’s position has rapidly become critical. I now threaten 38. Re8+ Kf6 39. Ne5 when he will either be mated or face heavy material losses.} 37...Bd6 38. Rc8 {This was a bit lazy. As soon as I had released the rook, I regretted not playing 38. Re8+.} 38...Kf6 {There was a chance to prolong the game with 38...f5, but I could still keep up the pressure with 39 g5} 39. Nh4 { After this move, heading for f5, I could no longer see any way for Neil to avoid losing material. His c-pawn, g-pawn, bishop, and even his king have come under increasing pressure, all because his pieces were tied down to the defence of the c6-pawn – a product of White’s typical minority attack in the Carlsbad structure} 39...g6 40. hxg6 fxg6 41. Rg8 Kf7 42. Rxg6 Bf8 43. Kf3 Ra6 44. g5 hxg5 45. Rxg5 Ra2 46. Rf5+ Ke8 47. Ng6 Bd6 48. Rh5 {I have to be careful to prevent the break ...c5 at a moment when the d-pawn is safe from capture.} 48...Kd7 49. Nh4 Bb4 50. Rh7+ Ke6 51. Ng6 Rc2 { I was pleased to see this as it enables my knight to reach its ideal post, back on d3. On 51...Bd6 I intended 52 Rh6 when only an engine might be able to hang on.} 52. Nf4+ Kd6 53. Nd3 Rc4 54. Rb7 c5 55. Rb6+ Kc7 56. dxc5 Bxc5 57. Rb5 {Either Black enters a lost king and pawn endgame, or he loses the d-pawn} 1-0

A masterclass from an expert on the Carlsbad structure.


What was Bobby Fischer's actual chess strength during the 1992 re-match vs. Spassky?

From wikipedia:

  Fischer's score of 17½ out of 30 (counting draws) against Spassky, rated 2545 at the time, gave him a performance rating of 2645, which would have put him at No. 12 in the world on the July 1992 list.


Do you find websites like chesstempo useful for improving tactical skills?

I have not played enough or practiced enough on ChessTempo to really notice a difference in my tactical ability, but I am probably certain that if you spend enough time and I am not sure how long this is (it varies for each person) that your tactical skill will improve over time.  I also never paid attention to my rating on ChessTempo as I do not know what my actual rating is.

One thing I am certain of is that ChessTempo and other similar websites or puzzles in books will teach you to stop and think before making a move no matter what or will teach you to look for a tactic — whereas before, I would make the first move I saw without thinking.

In the end, it probably does improve your tactical skills, you just have to be patient and not assume that your tactical skills are not improving by the number of games you win or lose.  We often grade ourselves on whether we win or lose and I believe this is a big NO-NO. Especially if we lose, we often assume that we have not improved tactically, strategically, etc.


The tie-break rules are listed on the FIDE website, D.II.02 paragraph G.14:

  The position of teams that finish with the same number of match points shall be determined by application of the following tie-breaking procedures in sequence ...

  (a) the sum of Sonneborn-Berger points, which are calculated as follows:
  match points of each opponent, excluding the opponent who scored the lowest number of match points, multiplied by the number of game points achieved against this opponent

So yeah, it's called Sonneborn-Berger, but it's different from the one you see in individual tournaments.

Let's see if this holds for the USA team:

GP  OPP MP   GP*MP

4   AND 10 (ignored)
3.5 SCO 12 = 42
3   ARG 14 = 42
2   CZE 14 = 28
3   SRB 13 = 39
2.5 UKR 20 = 50
3.5 IND 16 = 56
2   RUS 18 = 36
3   NOR 16 = 48
2.5 GEO 14 = 35
2.5 CAN 15 = 37.5
TOTAL:      413.5

We arrive at the same total.

(scores can be found here).


What are some of the main ideas in the Grand Prix attack?

You are correct in that Black's goal is to play ...e6 and ...d5, especially if White has played Bc4.

Some players will only play into the Grand Prix if Black has committed to an early ...d6, in that case, Black loses a tempo if he then plays for ...e6 and ...d5.


This is a better question than it seems at first glance.

Intuitively it seems possible to claim a draw, since the position appears to have occurred three times.

However, according to a strict reading of the rules, the position after 4...Ng8 has appeared only for the second time. The relevant clauses are 9.2:

  [...] Positions are considered the same if and only if the same player
  has the move, [...]

and 1.1 about the start of the game:

  The player with the white pieces commences the game. A player is said
  to ‘have the move’, when his opponent’s move has been ‘made’.

In the starting position, white does not "have the move" since black did not make a prior move, white merely commences the game. Therefore, the positions before 1. Nf3 and after 4...Ng8 are not the same, and a draw cannot be claimed yet.


This page presents a table of odds for rough ELO differences, used for games between a human and computer. Since my proposed difference is 900 points, this most closely matches the odds of removing a knight or two pawns.


Which is better, going for checkmate, or forcing immediate resignation?

you play a combination that is technically stronger since it forces mate, but it takes 8 moves, some of which are hard to see

If they're hard to see, chances are that you've missed something as well. Therefore, take the queen. You might miss the opportunity to finish the game in a beautiful way, but you can always save that for the post-mortem analysis.

The only reason not to take it would be if you're low on time and are not sure you can finish off the game, even being a queen ahead. But I wonder how you would see the mate in 8 then :)


The manufacturer of the Game Timer II clock used to give a good discount to anyone buying 5+, but that was before they were owned by Excalibur; no idea if they currently do.

In my experience running a chess foundation, most of the manufacturers are open to quantity discounts, but you need to contact them directly in order to find out what they are. (Often they will give you the same price they give the retailers.) Retailers like wholesalechess.com are often willing to do some discounting, but usually they give you a table on their website of where the quantity breaks come in. Sometimes the price breaks don't happen before 25 or 50, though.

Bottom line is it never hurts to ask.

As for what else, depends on what you're aiming for with the club. Boards, sets and clocks are all you really need to get going. Other supplies might include pencils and scoresheets for official games, a large demo board (or electronic display, depending upon budget -- we typically use demo boards with pockets on each square for the piece) can come in handy if someone is going to give demonstrations or lessons for the club members.


How do I determine whether a game is a draw or not in case of timeout?

As far as I know, every chess website simply looks at the opponents material to determine if they have mating material or not. It doesn't matter even if mate is possible.

The ruleset you are referring to are the FIDE rules, and for simplicity chess websites do not use these rules because the percentage of positions where self-mate is possible is too low.


I'd recommend Starting Out: The Scotch

It covers everything the Scotch has to offer, and it is written by an expert player in it.

Like the rest of the Starting out Series, it explains everything you will ever need to know on the opening. It offers great tips on whatnot.

There are lots of sources for minor stuff. Chess Caffe is a great source.

Also playing makes you understand it more. Hope it helps!


Existence Flanking against Center Control

This is a hard question to answer because you take a very broad, abstract, historical concept (the existence of "schools" in chess, with a particular list that I've definitely not seen before) and then you connect that with a very concrete, peculiar little thing (the moves Houdini suggests in the opening position if it doesn't have an opening book).

I'll just write a bit about both and then I hope you'll understand the difficulty. This is all completely my unsourced opinion and impression of current chess, I'm not going to give sources.

Those schools are a broad overview of the history of the development of chess strategy. First people thought one thing, then that got refined, then someone wrote a book claiming the opposite... That's interesting to read, but there are lots of reasons why it's not that useful to someone currently learning chess, in my view:

Reality wasn't as black and white as those "schools" make it seem. In the end, all of them played chess, they were good, and often if a strong move was available, they would play it. Some players used some techniques more often than other players did. And when they wrote books, they would argue vehemently against other books, because that sells.
That said, most of these discussions were pre-WWII, and the thinking nowadays is closer to what is "Soviet hegemony" in your list: if it works, it works. And since the coming of computers and their great defensive skills, we've found that there are way more things that work than we used to think. Flank openings, classical openings, extremely deep tactical lines, very quiet endgame openings, they all turned out to be playable. Both "hypermodern" and "classical" openings are extremely popular nowadays, and most players play both!
A discussion of "schools" is at such a high level of abstraction that you to wonder if that could ever help you find the best move in some concrete chess position during a tournament, which is in the end the only thing that counts when you're trying to get better at chess.

Then, Houdini. Chess programs aren't very good at the opening, compared to established opening theory. Some reasons why that is:

They don't need to be good at opening theory, because they use opening books. So they are tuned so that they perform best at the later stages of the game.
Opening theory is the compiled knowledge of hundreds of years of human research. Computers are strong, but not remotely close to strong enough to recompute the equivalent of that research in a couple of minutes.
Even if they were, thousands of people have computers running continuously to work on openings, and your single Houdini is up against that too.

So, forget about using Houdini in the opening position. Look at what is popular among strong players. And they use a broader selection of openings than ever.


What are the standard time controls for live chess (non-OTB and non-correspondence) on every chess websites?

What defines, "standard time controls"? Do you want the most commonly played time controls? Do you want the time controls which are suggested per each server?

To me, a more interesting analysis is to plot the percentage of games played vs time control and find the time controls with the largest spikes (popularity). But, I'm not sure how to get that information.

On ICC, the most popular time controls would likely be 3 0, 5 0, and 1 0. They have different auto-pairing pools for some standard time controls as well, each has a separate rating. This includes, 1-minute, 5-minute, 15-minute, and 45-minute. Although, 45 minute online is not very common.


Move generation has been tested to death in modern chess engines, and the current consensus is that the following two approaches are optimal for sliding pieces:

A lookup table indexed by PEXT of the relevant occupancies ("Fancy PEXT Bitboards")
A lookup table indexed by the higher order bits of the product of the Bitboard of relevant occupancies and a magic multiplier ("Magic Bitboards")

Option 1 is preferred on CPUs which have a fast hardware PEXT (i.e. Intel Haswell and newer, no AMD CPUs at the time of writing). Otherwise, Option 2 is preferred.
For example, stockfish offers bmi2 and popcnt builds: the former uses PEXT bitboards, the latter uses magic bitboards.
Kogge-stone
The Kogge-stone fill algorithm doesn't tend to be used in top engines for the simple reason that it benchmarks as being worse than the alternatives. I can offer a few reasons as to why this might be the case, but it is more important to recognise the fact that it is the case:

They require a ludicrous number of CPU instructions. Each ray that must be cast (of which there are four) requires 5 shifts, 5 bitwise '&'s, and 3 '|'s, while the lookup operations only require 3-5 instructions per slider.
While Kogge-stone can in theory be vectorised, there tend to not be enough sliders on the board to take advantage of this. For example, there tend to only be 3 (or fewer) rook-like sliders on the board at any given time. This makes the parallelism not worth the speed tradeoff.

 Actually improving move generation
A few things to note based on your code:

Use x & (x - 1) to clear the least significant bit: this is faster than x &= ~(1 << from)
Don't recompute the mask at every iteration: do it before the generation loop instead
Use magic bitboards or PEXT bitboards: this is faster than Kogge-stone
Make sure that hot move generation functions (like GetRookMoves) are inlined.


It is not checkmate if the other player has any legal move that gets them out of check. Capturing the checking piece is one such way; whether the capture is en passant or not is irrelevant for the purpose of this question.

In this case, an en passant capture is the only legal move. If the other player didn't know the en passant rule, I suppose they might lose on time unless they figure out what's going on first. Using a website such as chess.com one might be able to discover the rule accidentally, since clicking on a piece normally highlights all the possible moves for that piece.

Regarding your question of "what happens in the case the opponent plays some other piece", that would be an illegal move. A site such as chess.com simply won't allow it. In an over-the-board tournament, the consequence may vary: in blitz, the player who makes the illegal move loses; in long games, the move gets retracted and a time penalty is applied, at least for a first offense.


What are some good defenses against the king's gambit?

The best way is Fischer's way. he had a low opinion of it, and so he wrote an entire paper on it's neutralization. Here is the paper and here is his proposal

[Title "King's gambit bust!"]
[StartPly "6"]
[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

 1. e4 e5
 2. f4 exf4
 3. Nf3 d6

What have we achieved here.

Our opponent is a pawn down
Our bishop is freed, pointing at the somewhat weakened kingside. With the idea of Bg5 and other threats.
The knight jump on e5 isn't a plan anymore
Lots of ideas for black.


Beating the King's Indian Defense: strategic ideas?

You do not say why you lose: Are you being beaten positionally, or are your opponents successfully attacking your king?

This a VERY difficult question to answer since it is such a large opening to cover (the Vassilios Kotronias books on the King's Indian from Quality Chess are 5 volumes!).

Basically, what you are looking to do is play on the queenside, and prepare c5 in most lines of the King's Indian, and open the c-file, and penetrate with your pieces. Black, especially in the classical main line, is looking to attack your king.

If you are being beaten positionally, then you really need to study the ideas behind the opening more closely, and that is way beyond the scope of this question. If you are being beaten by all-out assaults, then you need to either learn a lot more theory, or do what I do sometimes: Play g3 and Bg2 lines, which make it more difficult for direct attacks to succeed.

In the position you gave, it is black to move, and he can plant the N on c5, and fortify it with a5, which stops the immediate b4 since Nc5 gains time by attacking e4. I am going to give a few lines to give you an idea of how play might go, but I also think that you should vary on move 8 with 8.Qc2, which is more flexible (make sure you read the extensive note after 9.d5 explaining why this ends up better). 6...Nbd7 is rare for a reason, and your 8.d5 does nothing to try and punish it.

 [FEN ""]

 1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. Nc3 d6 5. e4 O-O 6. Be2 Nbd7 {This is very rare, and can lead to an excellent game for black if white just plays by rote. White should vary on move 8.} 7. O-O e5 8. d5 (8. Qc2 $1 c6 9. d5 {And black has a lot of options, but this is a better setup for white to combat them. One of the following happens: The c-file gets opened and white gets better chances to use the queenside; or a Rd1 will pressure the d6 pawn if black does not exchange; or if that pressure on d6 forces c5, then a3, and b4 will be possible (with Rb1), all the time while black is denied the c5 square for the Nd7.} (9. Be3 {Is also good, but you need to know a lot of theory.})) 8... Nc5 9. Qc2 a5 {Eventually, white wants b3, a3, Rb1, and b4, but you must be careful of tactics with the Rb1 and Nxe4 ideas followed by Bf5. For example:} 10. Bg5 (10. Rb1 $4 Nfxe4 11. Nxe4 Nxe4 12. Qxe4 Bf5 $19) (10. a3 $2 {This is why b3, a3, and only later b4. It cripples the white queenside.} a4) 10... h6 11. Be3 b6 12. Nd2 Bg4 (12... Ng4 13. Bxg4 Bxg4 14. a3 $1 {And b4 next since a4 loses a pawn.} a4 15. Bxc5 bxc5 16. Nxa4 {But black does have some compensation after Qg5.} Qg5 17. f3 Bd7 18. Nc3) 13. f3 Bd7 14. b3 Nh5 15. Rfe1 {To prepare Bf1 after nf4, and white will continue with a3 and b4.}

In the end, it is about opening the queenside while not getting mated. You want to defend any kingside threats as economically as possible, while trying to distract black on the queenside. If you penetrate quickly, and actively, any attack is often doomed to fail.


Have any top players intentionally thrown a game for tournament reasons?

Yes.
But not very many incidents.

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


The engine is recommending Qc1 and I cannot figure why it is the best

Consider the position before 15. Nc4.
[FEN "r1b2b1r/ppp1k1pp/8/4p1N1/4P2n/1B1q4/PP1N1PPP/R2Q1RK1 w - - 0 15"]

You have developed two knights, a bishop, and castled. Your opponent has developed a queen and a knight, and his king is stuck in the center.
In other words, you have a massive dynamic advantage! You are already in position to leverage your superior development & king safety and steamroll your opponent off the board. There are plenty of ways to do so - Rc1, Qc1, Qh5, they all produce immediate threats against your opponent's king that are hard to fend off. These moves even come with tempo because Black can hardly allow Qxc7+ or Qf7+.
Nc4, on the other hand, allows your opponent to trade queens. When you are on the attack this is one of the things you least want to do, because the queen is the most powerful piece and  hence also the most powerful attacker. After 15. Nc4 Qxd1, you still have a comfortable advantage, but you are no longer playing for immediate checkmate.
I haven't looked at the computer's suggestions and it probably sees something more concrete, but still: on general grounds, trading queens in this position is a bad idea. By extension, that makes Nc4 an inferior move.


Is there a chess AI that can force checkmate on a specified square?

Thanks for the great question ChessNoob3000, and welcome to chess.stackexchange.com

I don't know of any chess program right now ("AI" or otherwise) which can force checkmate on a particular square. The idea of "conditional problems", e.g. white must mate with a certain piece, was popular in the 19th century, before the arrival of software which can solve much more complex problems, but they are now a bit of a backwater. If you wrote a program specializing in conditional problems, you could be able to apply it to hundreds of unproven problems!

Related work is in Francois' Labelle's "Jacobi" program. This does allow for conditions, but is strictly applicable to help problems and proof games. It would not apply to adversarial stipulations e.g. "mate in 2" or "self-mate in 2".

You might post a feature request for Popeye in github , or if you are a programmer you might want to contribute to the Popeye open source yourself. Chat with Thomas Maeder about this: conditional problems for non-help stipulations is definitely a hole currently.


Stockfish isn't a perfect chess-playing entity, and you've found a position where it's unable to tell is a draw (at least until the 50 move rule kicks in and helps it prune). These positions are called "fortresses". You can tell this is happening because even if you input the solution, Stockfish still evaluates the final position as -10 or more. These fortress positions where Stockfish is dead wrong are few and far between, but they exist, and this is one of them.

There've been various attempts at writing fortress detection code in Stockfish and other conventional engines which are meant to recognize fortresses and stop Stockfish from heading for them if its position is superior. If you have a smart idea, you can probably publish it in an academic journal (see the publications in the chessprogramming wiki).


Since the question is about Chessable, I thought I'd pitch in :) If you use Chessable's Explorer Tool you will be able to navigate to a position such as

d4 Nf6 2. c4 e6

and then see which options are available to you and their win rate.

For instance 3. a3 scores 36% W, 22% D, 42% B, so if you are White, you can see it would not be a good opening to pick.

By browsing like this, you can find good options and add them to your repertoire and try to avoid complex theory. You can also turn the engine on that page and check the lines with the Engine for possible continuations.

However, in my opinion, if you want to play out of theory the best thing is to pick some openings that are known for their relative lack of theory and see if a complete book exists on it (free or otherwise). For instance, Fianchetto systems or the London System come to mind as ways to play where you can play without much theory.

As Black, I've had a Master play things like the Pirc/Modern against me where they "wait" on the third rank for you. They did not seem to be playing theory but rather just a standard set of moves (fianchetto a bishop, play e6, etc.). I had a better position but since they took me out of theory into murky waters, eventually their time advantage paid off, and I lost. Presumably, this is what you are trying to do? :)

Having said all that, this week we are releasing a new book by a renowned French chess coach that has relatively little theory and guides you to sound openings where your opponent can quickly get in trouble. So stay tuned and look out for it!


I've mulled this over a number of times.  Here is what helps me play better with a knight.  I offer it not as a general solution, but as a solution that has worked for me.  I hope you find it useful:

Understand how the Knight moves COMPLETELY.
Understand ALL the Knight threatens COMPLETELY.
Understand that the value of the Knight relative to the Bishop may change.
Understand by colour, what the Knight threatens when he sits still or moves twice (Rule of Even).
Understand by colour, what the Knight threatens once he moves (Rule of Odd).

  Point 1. Most people know how the Knight moves described as a "L".  I've found this to be inefficient since this is only visualizing one of his possible moves and it's possible to miss some of his possible moves thinking this way.

To truly see his potential a player needs to know all of his possible moves at once.  Here's how I visualize it (and will try to explain clearly how I see it):

  Around the Knight is a box the corners of which match the colour he is sitting on.  The Knight jumps outside of the box to the opposite colour squares touching the corners.

It is possible to look at a board and see this "box" while playing and see all of Knights potential moves at once, rather than just one.  The ability to see this box rather than a single move is something of an epiphany.

  Point 2.  Understanding all the Knight threatens at once, rather than a single threat allows the player to understand all the pieces he can attack.

Just as above (Point 1) where seeing all of a Knights moves show his true potential, seeing all he threatens shows all of his attacking potential.  Many players identify what he threatens (in a somewhat sequential manner) one threat at a time.  However, this is inefficient and may inevitably miss some.  The ability to visualize his box allows a player to see all he threatens which allows a player to realize his full attacking potential.

  Point 3.  Some theories of Chess don't assign the Knight a static value relative to the Bishop (meaning the same unchanging value). Consider this for a moment:

If the Bishop works best on an open board with far reaching open diagonals BUT the Knight can jump around pieces on a crowded board but whose reach is always limited, it stands to reason the Bishop's value increases over time as the board opens up and as the game goes on; whereas the Knight's value decreases overtime since the board opening up removes his advantage.  Accordingly, consider assigning the Knight a value of 3.5 in the beginning of the game (Bishop at 3.0), and flip these values as the game goes on as it's appropriate.

  Point 4. An un-moved Knight threatens the opposite colour he's sitting on (or if he moves twice).

A Knight on BLACK is threatening WHITE.  A Knight on WHITE is threatening BLACK.  Remember this and consider it when considering position.

  Point 5. A moved Knight threatens the same colour he sat upon before moving.

A Knight moving off BLACK will threaten BLACK once he comes to rest.  A Knight moving off WHITE will threaten WHITE once he comes to rest.  Remember this and consider it when considering position.

These last 2 points really help in end-game situations where you're forced to chase an odious opponent around the board.  If you want to threaten the same colour you sit upon, you must move. If you want to threaten the opposite colour, stay or move twice.

Good luck!


You are talking about playing suboptimal moves for bluffing. Stockfish is not good at that... Chess programming theories are no good because it’s hard to define a complicated position. There were research articles on this topic but it’s still an unsolved problem.

I believe you will need a good mathematics model. Stockfish doesn’t have it.


What is the purpose of editorial comments in Informants?

RR = Redaction Remark, meaning they consider recommended line to be better, or that the game/line they pointed out is relevant...

{Credit to AlwaysLearningNewStuff's comment above}


Is the Reversed Sicilian / King's English 1. c4 e5 more of a positional and quiet opening or a wild and tactical opening?

I would definitely classify these positions as rather quiet. Black is lacking the tempo to build up an attacking position, like white does in the sicilian:

For example in this line the knight usually goes back to b6, something white (i.e. Nb3) would never play against the dragon. And of course d4 is much easier to achieve for white here, than d5 is for black in the sicilian. That'll lead to some exchanges with white banking on his strong g3-bishop.

[FEN ""]
1. c4 e5 2.Nc3 Nf6 3.g3 d5 4.cxd5 Nxd5 5.Bg2 Nb6

Of course you still have to pick the right subvariations to avoid sharp lines, but that should be an achievable task. If I knew a variation that forces a sharp tactical fight onto white, I would play it with black. But I don't.


What's the meaning of "%evp" in a PGN comment?

A similar question was asked by GM Tony Kosten on the chesspub forum back in January:

  Looking at the last set of PGN files I received, at the beginning is a
  new tag followed by lots of numbers, like:

  {[%evp
  0,96,30,30,22,1,30,2,2,-9,-3,-44,23,23,21,32,41,37,44,23,22,18,26,11,22,
  -4,0,-1,8,7,7,14,9,5,16,8,38,16,22,19,25,54,19,19,22,22,22,20,20,20,24,-18,24,
  -53,-53,-61,-61,-56,-23,-20,41,41,39,39,35,30,44,44,33,50,70,70,75,75,75,75,75,
  56,60,59,62,56,68,56,50,48,48,40,46,60,49,30,48,47,47,59,46,56,57]}

  I assume ChessBase 15 generates this when it quickly analyses games
  when you open them. However, is this a standard PGN code, can other
  chess programs read it?

The original PGN standard was created and published in 1994 by Stephen J Edwards. Here is a copy of his original standard: Portable Game Notation Specification and Implementation Guide. By 2001 he had dropped out of the project when this supplement was published to the PGN standard. There it defined a new embedded command string which would be marked by a starting "[%".

  3.2 A generalised format for embedding commands in comments.
  3.2.1 Position
  An embedded  command may occur at any position in a standard PGN comment, ie  between { } . For example: {Optional leading
  comments [%clk 1:05:23] optional trailing comments} where  [%clk
  1:05:23]  is the embedded command string.

  3.2.2 Structure The command string is structured as follows.

  A leading tag of [% A command name consisting of one or more
  alphanumeric characters. A space character. Either a single parameter
  or a comma delimited list of parameter values. A closing tag of ]

So, "[%evp" is an embedded command, first seen in Chessbase 15 output. As such it is Chessbase 15-specific until such time as Chessbase publish how they use it, at which time other pgn producers/consumers can start using it too.

My speculation, FWIW, is that it is part of Chessbase's "Chess Position Trainer" and is intended for Chessbase internal use only.


Why, in online chess, is it that the shorter the time control, the higher the world leading elo is?

I think the key of this is number of played games.
Nihalsarin2004 9440 bullet games
konevlad 1113 blitz games
Zhigalko_Sergei 257 rapid games
Biranidun  84 clasic games


Connecting Chess Engine with a Java program

Let's break it down:

You have a working Java chess board that you can use to move pieces
You want a chess engine (engine is a more precise term than AI)
You want to download Stockfish and use it
You want to invent a new protocol or technology to communicate your chess board with the Stockfish engine

To me, your question is really:

How to connect an external chess engine such as Stockfish within my own chess GUI in Java?

Useful old posts in this site:

Chess Engine API
What is the optimal way to use Stockfish programmatically?

Basically, what you need to do is:

You shouldn't invent your own technology, you should study the UCI protocol. http://wbec-ridderkerk.nl/html/UCIProtocol.html is a useful reference. I can get you started, do this:

Download Stockfish
Open Stockfish in a console/terminal, don't double-click on it with your mouse
Type ucinewgame and then go movetime 1000. Do you see Stockfish's move?
Read the protocol specification and learn how to analyze a position, and the output format.

Write a UCI output parser. Parse whatever information you want.
Use the information to make a move on your chess board.

The only technical difficulty I can see here is to establish a "connection" between your GUI with the engine. This is done by creating a new process, running the engine.

  https://stackoverflow.com/questions/2006035/how-to-create-a-process-in-java has information on how to do it.

Once you have the new process, you can establish a simple standard input/output pipeline. https://stackoverflow.com/questions/27081918/java-how-to-send-a-value-to-child-process-using-outputstream has the details. Ask on Stackoverflow if you're not sure.


I think that's your question:

Q: How does a chess engine evaluate a chess position and give centipawns score?

I don't want to bore you with technical details, let me give you simple explanation:

Chess engine is able to evaluates a chess position and give a score

The score can depend on many factors, including but not limited to:

Material
Pawn structure
Mobility
King Safety

  https://chessprogramming.wikispaces.com/Evaluation

Chess engine searches as many moves as possible and compare the moves by evaluation score. The best move is the move that gives the best score.
Now we know a chess engine can give a score. For convenience, they scale the scores to centipawns.


Why Kirsan Ilyumzhinov is so popular in the chess world?

I thought that Nigel Short summed it up pretty well here: http://www.chess.com/news/breaking-ilyumzhinov-beats-kasparov-110-61-at-fide-presidential-elections-4528

"There's nothing wrong with chess players. If you ask in the playing hall, I'll bet 9 out of 10 will vote for Kasparov. The problem is: delegates. If the delegate has received an incentive to vote in a particular way, it doesn't matter whatever reason or logic is presented to him."

Basically, many delegates voting for Ilyumzhinov received some strong form of compensation to do so. He consistently wins because he has money (much of which he gained while ruling Kalmykia) and has zero moral compunctions about how he uses it.


Are Bronstein delay and simple (US) delay really equivalent?

They are equivalent.
With Bronstein, the time is added after the move - it has to be, because before the move you don't know whether or not you'll take the full amount of the delay time. However, perhaps what you're missing is that the first move has the delay time added. So if you start a game with 10 seconds on the clock and a 5 second delay, the Bronstein clock would actually read 15 seconds at the start (and start counting down right away) while the normal delay timer would read 10 seconds (and not start counting until 5 seconds had passed.)


Why does Black want to trade off her King's Bishop in many d4 lines?

Black gains a tempo. Black has played two bishop moves, but white has played Nc3, a3, and bxc3. Once the smoke clears, black has a lead in development with one minor piece out (vs none) and can immediately castle. Also, it doesn’t hurt that the doubled pawns are a weakness that can be exploited later.

If white does not play a3, black has no immediate need to take the knight, and it makes more sense to keep the pin. This is especially true because black does not gain the tempo without a3.


What is the state of the Panno variation of the King's Indian Defense Saemisch?

The Panno is a sharp line that has received a lot of attention lately, particularly the variation below where White opens the centre favourably. The variation isn't refuted by any means, but Black players have found this variation to be uncomfortable.

[FEN ""]
[StartPly "12"]

1. d4 Nf6
2. c4 g6
3. Nc3 Bg7
4. e4 d6
5. f3 O-O
6. Be3 Nc6
7. Nge2 a6
8. Qd2 Rb8
9. h4 h5
10. O-O-O b5
11. Bh6 Bh6
12. Qxh6 e5
13. dxe5


Is there still any top grandmaster who still regularly plays Queen's Gambit Accepted?

Of players who have been inside top ten it is Ponomariov who uses this opening the most often. Ivanchuk plays it too, but then again he plays most anything. And Nakamura played it a few times last year.

You can do searches for free online at 365chess.com.  Here is an example:
http://www.365chess.com/search_result.php?search=1&p=1&m=4&n=109&order=belo&ms=d4.d5.c4.dxc4&rev=&start=50


Looking for free online chess engines that have (roughly) known ratings

http://www.computerchess.org.uk/ccrl/4040 gives you a huge list of engines with their CCRL rating. Please note CCRL rating is not directly related to the human FIDE rating, but it's a reasonable estimate in any case.

I recommend you my engine apps. They're free and very popular. Please visit my site to try my chess apps:

http://www.smallchess.com

You'll find a Stockfish app with adjustable playing strength. You'll also find my own chess engine in the SmallChess app. There is also a Chess Mini app, that plays interesting chess at around FIDE 1800 to 1900. Apart from simply just playing, you'll also receive useful feedback, for example:

It's obvious the great Nimzowitch had been winning most of the game. The graph will tell when and how you blunder.

Now, back to the rating. While the SmallFish app (Stockfish engine integrated) allows adjustable playing strength, the rating reported in the app isn't very accurate. The confidence interval is roughly about +-200 Elo. The rating range given in the SmallChess app is much more accurate, because I'd paired it against human players on the FICS server.

I'm sure you'll learn and improve your chess by playing my apps.


You should always be skeptical about the "inaccuracy" annotations you get from Lichess (or similar sites) because it runs an extremely quick analysis; the small differences in evaluation that get called inaccuracies may go away when you let the engine run deeper. (Blunder annotations, on the other hand, are much more likely to be meaningful.)

While the engine initially liked Qc2 best, after letting the analysis of your position run to "completion" (depth 25) with 5 lines, the situation changes. Your results may vary because it's not even completely deterministic, but here's what I got:

As you can see, the "best" move now is to castle! But the first four moves are practically tied, between +0.7 and +0.6, and the two moves you mentioned, Qc2 vs Bd2 are now both at +0.6. At some points while the analysis was running, Bd2 was actually ahead. And I'm sure if you let it run longer (there's the "infinite analysis" option for that), they may trade places yet again.

In practice, they are both good moves as far as the engine can tell you, so you have to decide based on human factors or personal preference. For example, castling looks like it might lead to losing a pawn. Stockfish doesn't mind it, maybe because it can "see" the compensation (or how to recover it several moves later), but you might not be comfortable risking it.


Are there any methods to encourage the engine to go for mate rather
than a massive material imbalance?

Any reasonably sophisticated position evaluation function is going to give extra points for certain positional elements (passed pawns, advanced pawns, bishop pair, etc.) and deduct points for other negative positional elements (doubled pawns, isolated pawns, bad bishop, unsafe king, etc)
Obviously any halfway decent evaluation function is also going to handle positional elements like checkmate (add MAXINT), stalemate (assign 0.0), 3-fold repetition (0.0), 50 move rule (0.0), insufficient material (0.0), etc.
If all your evaluation function does is use piece values and nothing else then you still have a lot of work to do to have an engine that is any good.


Why move the queen’s rook to defend d-file instead of king’s rook?

White needs to find a way to make use of his extra pawn, because it is hard to see any other plan. His dream would be to play d4-d5-d6, but this is not yet possible because a) d5 is under Blacks control, and b) the Pe5 would hang. Having the Rooks on e1 and d1 would address both of these issues, and that would be a motive to choose Rad1, but there is still play in this position and White needs to be accurate.  Whites K is extremely safe, so that is not a concern. There is no reason to worry about Bxf3. The resulting "weak" pawns do not matter because they cannot be attacked. Best in this situation seems be Bb5 which forces either Bd7 or Nd7, both of which reduce the effectiveness of Blacks blockade. A plausible continuation after 1..Nd7 would be 2. Ng5 threatening Bc4, 2..h6, 3.Ne4 intending Nd6. So Black will have to play ..Bd7, and then White can play Bxd7 and reorganize at leisure. He might consider putting the KR on d1, followed by a Knight move and f4. The QR is then free to occupy the c-file. It is too soon to analyze to a clear conclusion, but I would certainly expect White to win.

This discussion is based on specifics of the particular position, and not on appeal to any general principles. That is almost always the way to go.


Why is closing the center by White generally considered a concession?

The pawn advance reduces the potential, what is done cannot be undone and Black uses the information to set up accordingly. This is probably the broadest and most general explanation. In the end, however, it may turn out to be a matter of taste or fashion.


There is nothing in the rules about this.

The way that grandmasters set up their knights varies from person to person.

Here is an image from the world chess championship:

Carlsen has placed his knights facing each other, and Caruana has positioned his knights facing forwards.


Which format should i choose to improve my chess skills (Blitz chess or Standard time control chess)?

Will blitz help more than standard time control to improve my chess
  skills?

No. Standard time control chess always helps more to improve your game than blitz chess because in standard chess you spend more time analyzing the game.

Chess is a game of intelligence but even more so of knowledge. The more (structures, endgames, openings, etc.) you know, the better you are.

  To make a rather primitive classification, the average grandmaster
  knows about 1,500 - 2,000 typical positions, including the opening,
  possible middlegame plans, and some outlines of endgame. Super GMs,
  like Kramnik or Anand, have a wider and deeper knowledge. As for
  Kasparov, his knowledge is truly head-spinning, I guess, his number of
  positions might exceed 10,000. Garry's memory is phenomenal! I think
  it even impedes him during the game. - Valeri Tsaturian

Knowledge is hardly acquired in 3-5 minutes (blitz) and even if it is, it is quickly forgotten. To gain chess knowledge, you need to spend more time studying the game.

The more time you spend studying a position, the more you understand it, the better you remember it, and the more insights you gain into it. It also helps you correct your faulty decisions in the post-game analysis, because, if you're wrong, it can show you to what extent you're wrong in your judgment of certain positions.

For example, I played a game recently in standard time control and in one position, my opponent was really surprised that I didn't capture his bishop with my knight. During the game, I thought that the trade of bishop for knight wouldn't help me in that position, but in the post-game analysis, my opponent proved me wrong and demonstrated how it was good for me. I went home and analyzed with a computer and found that my opponent was right. If this had been just a blitz game, I could have just excused myself saying "well, I didn't have enough time to consider the consequences of that" and thereby prevented myself from recognizing this flaw in my own knowledge.

  If No when and for what purpose should i play blitz?

You can play blitz to

1) Enjoy yourself.

2) Check your opening preparation.

3) Develop a rough understanding of certain types of positions with the intention of analyzing them in depth later. This third point is crucial, because it is the best way to use a blitz game. You may not learn much during and immediately after the game, but if you analyze your blitz games, you will still learn a lot.


What is the legend of Ossip Bernstein, who supposedly played chess to save his life?

The written sources appear to be:

An obituary on Bernstein by Edward Lasker (a friend of Bernstein) in the April 1963 issue of Chess Review, which is described in the link below, including a scan of the 1963 article itself: http://jewishchesshistory.blogspot.com/2009/09/alekhine-escaping-execution-definite.html

However, the US Chess Federation has made it also available on their site on page 104: http://uscf1-nyc1.aodhosting.com/CL-AND-CR-ALL/CR-ALL/CR1963/CR1963_04.pdf

A book by Arnold Denker, mentioned in the Wikipedia article itself, 'The Bobby Fischer I knew and Other Stories'. Denker seems to indicate that he also heard the story from Bernstein himself and that he always believed it.


How do I prepare against someone if I have a database of his games

First of all, I don't think that chesstempo or other sites are actually good for preparation. I just took a look and saw that there are only 9 moves of each game displayed. If you are taking chess seriously, it's better to get the chessbase or at least fritz. They are more user friendly and statistics are better.

Regarding your question's title. Preparation is a complicated process. It depends mostly on time you are willing to spend on it. If you got tons of time and the game you are preparing to is very important, you should totally x-ray your opponent looking at all the games. Probably with someone more experienced in order to advise you a little bit.

Anyway, some basic stuff:

Check what openings your oponent play and what is his win rate/draw rate/lose rate, you know why.
What is your standard answer to his opening? Do you feel comfortable with it? What's your W/D/L ratio there? Are there game of YOURS in database? Keep in mind, your oponent might be prepared aswell!
Are there any games/variations that your oponent has a big lose rate? How well do you understand those positions? Do you know any similar structures that you could drag him into?

So in simple words: spot the weakness and exploit, that's it.


Who said "One bad move nullifies forty good ones"?

According to chesshistory.com, in October 1959, Al Horowitz wrote:

  It is axiomatic in chess that it is easier to achieve a winning game
  than to win it. One bad move nullifies 40 good ones, and precision
  technique is of the essence even when the game is well in hand.

The same can be found in his book, “All About Chess”, written in 1971.

However, in the Chess Review magazine (November 1961), Al Horowitz calls this quote an “adage”.  Given this, I think that Al Horowitz is not the author of the quote, but thanks to him we know about it.

As for Bernhard Horwitz, I have not found reliable sources indicating that he is the author of the quote. At least, it is strange to me that it is not mentioned in his books.


Why did Bobby Fischer quit chess after the match with Spassky?

There is no real definite answer for this question.  Many people have floated different theories, most of which borrow bits and pieces from each other.  It is quite possible that his mental struggles just got the best of him or that he lost interest after attaining the summit of the game.  Psychologically, it must have been hard to cope when you get the thing you've been working for most of your life.  In My Great Predecessors, Volume IV, Garry Kasparov offers a few reasons, arguing that Fischer probably would have lost to Karpov and probably knew it (that point is debatable).

Regardless, Fischer forfeiting the title was not without precedent in his career.  He dropped out or quit major competitions or chess itself on more than one occasion.  In fact, despite his spell of dominance in the candidate's and title match, his career had almost always been erratic. The reasons for this are debatable as well--I've seen people argue that it was mental illness, strategy, or just intimidation--but the answer is probably a mix of reasons.


3.Nce2, followed by Ng3, Nf3, Bc4, O-O, etc. is reasonable.

A thematic game to reference is http://www.chessgames.com/perl/chessgame?gid=1186636

In general, however, 2.Nc3 isn't known as the best theoretical response.


Is there a Unicode-compatible alternative to PGN?

https://sourceforge.net/p/pgn4web/wiki/PGN_Support/

if you read that, you will notice:

 in order for pgn4web to display those characters correctly, the PGN file should be saved in unicode UTF-8 format.

you can save PGN as UTF-8... Just open notepad > Save As... > Encoding and select UTF-8. and you can then add the appropriate player names! I've tested this, and it works with Arena Chess and a few others...

Hope this solves your problem. ~CSS


Queen versus rook endgame: to check or not to check?

For a human, winning Q/R against a computer is more difficult than expected. Indeed, the key is not checking itself but avoiding that the rook checks the king away. Of course, the best concrete strategy in some position may giving some checks first, just to lead the Q to the correct field without losing a tempo. Note that in the final position the Q controls the vital a3 field. Also observe that 1.Qc6 is fastest, but not most lucid in terms of human strategy. I surely had begun with 1.Qh5+ and trying to convert it into the Philidor position. But also here the trick is that attacking the rook hinders it on returning, e.g. : 1.Qh5+ Kg3 2.Qh1 (again, losing a tempo is more elegant, Black to move will be forked quickly) Ra2! 3.Qf3+ Kh2 (otherwise a fork comes soon again) 4.Qd5! (the key move) Rg2 5.Kf3 Rg3+ 6.Kf2 and again, Black is out of checks. (The point being, after your king lands on f3 uncontested, the defense collapses.)


Willingly giving up castling rights in the opening?

Weaknesses like doubled/tripled pawn structure, color complex holes, and right to castle only matter in chess to the extent to which the opponent can exploit them. In the Old Indian variation you gave above, yes, Black lost the right to castle, but is White in any real position to exploit it? The answer is no. In fact, Black's king is very safe after he plays c6 because he can then tuck his king into c7 and there isn't any real way for White to even check him. The pawn and c6 prevents Nd5 and Nb5 checks, and Bf4 check isn't gonna work because Black will probably post his bishop to d6 and/or play e5, so his king is clearly not "weak" despite the loss of castling rights.

There is another position in the Sicilian Four knights that goes something like:

[fen ""]
1. e4 c5
2. Nf3 Nc6
3. d4 cxd4
4. Nxd4 Nf6
5. Nc3 e6
6. Nxc6 bxc6
7. e5 Nd5
8. Ne4 Qc7
9. f4 Qb6
10. c4 Bb4+
11. Ke2

While Ke2 aesthetically looks ugly because it loses castling rights and also blocks the light-squared bishop from developing, the point is that after Ke2 - f3, the king is extremely safe. If you look at that position yourself, I challenge you to even come up with a plan for Black to check the white king. If you can't, that's okay, because White's king is quite safe on f3.

Here is a counter example. This is from a game I played recently actually where I'm black.

[fen ""]
1. e4 e5
2. Nf3 Nc6
3. Bc4 Nf6
4. d3 Be7
5. Nc3 O-O
6. Be3 d6
7. h3 Na5
8. Bb3 Nxb3
9. axb3 d5
10. exd5 Nxd5
11. Nxe5 Nxe3
12. fxe3 Bh4+
13. Kf1

Here, Black has sacrificed a pawn to force White to lose castling rights with the annoying Bh4+. Notice though that there are a number of factors in this position that makes losing castling rights much more serious in this position than in the previous position. First, Black has the bishop pair which alone is good compensation for the pawn. Second, White has all these dark square weaknesses on g3, h2, and f2, and Black has the dark-squared bishop. White also lacks his own dark-square bishop to protect those squares, so it only heightens the problems of losing his dark-squared bishop. Third, White's king position here impedes the development of his h1 rook, so his pieces are more awkwardly placed.

You can argue Black has lost a pawn, but I would argue that the pawn sac has forced White to lose a rook, because it will be very difficult to get his h1 rook into action. All these factors make losing castling rights here really really bad for White because Black has these compensating factors that allow him to take advantage of White's compromised king position and loss of castling rights.

So the takeaway from this is that with any weakness—be it losing castling rights, or pawn structure weaknesses—a weakness is only a weakness if it can be exploited by the opponent. In all mainline openings where one side loses the right to castle, or takes on any other sort of weakness, it is because that side willingly loses the right to castle because his king position can't be exploited and because other aspects of the position trump king safety/castling rights.


Possible game result combinations in a FIDE tournament report file

One additional set of result combinations arises if you are unrated but about to get a rating and you play a rated player. Then, because you are unrated, the game will not be rated for your opponent but, because it forms part of your results which give you a rating, it will be rated for you.

Hence, you can add (1,6), (2,5) and (3,4)

PS I've edited the title of your question because the original was almost identical to this already answered question - What are the possible results of a game?. However you are asking something different.


Can black play for a win? Heck yes! This is totally won for black.

I did not even realize you were up a pawn at first, and I was thinking there is a clear plan here.

First, here is the analysis of the position.

You are up a pawn.
You have the better minor piece.
White is weakened on the queen-side since black can put a piece on c4, and b3 is just horrible then leaving c3 super weak, so that cannot be played.
f4 has also weakened white's king-side.
Black has a clear, and simple plan.

Here is the plan for black:

Black's play is on the queen-side. He will gradually push the pawns, carrying out a "minority attack". That is when a smaller number of pawns push and trade down against a larger number, leaving the larger number with one remaining, but weak, pawn.
Play Rc4 right now so there is no time for Nd4 hanging f4 to Bxf4.
Bring the other rook to c8, and then the Q goes to f8 and over to the queen side too.
The Bd6 might even redeploy to g7 to provide additional defense against any white all-out attack on your king, while still hitting the queen-side.
Then play a6 (or maybe a5 in one go), b5, a5 and then b4. After trades, white will be left with either a b-pawn or c-pawn, which can be attacked by the black major pieces, and possibly the black bishop. It is possible that the black major pieces will have to be redeployed to help execute b4, for example a Rb8, or the queen helping. It is also possible that one might go to a8 to take control of that file after some trades.
Win the extra pawn, and then push your central pawns and win.

This plan is very common, and even if black were not up a pawn here, this would still be much more pleasant for him.