Is attempting to capture the king advisable in this position? This position occurred in a game of quantum chess recently:

Is trying to take the king with the queen worth the risk?

My reasoning for this is:

If the bishop is on a2, white can take the king and win the game.
If the bishop is on f7, the queen cannot capture the king, the rook on b1 is safe, and black is able to move the rook on f5 out of danger.

What line would follow if the king capture fails? Would it be more beneficial to ignore the possible check and take the rook on f5? What would the best line be from there?

Confused?

You can check out the rules for Quantum Chess, or read the post written by creator Chris Cantwell.

Interesting!

Based on probability lets say we the bishop being in a2 is equally probable as being in f7 (principle of superposition, quantum chess rules).

Taking queen with king is blocked if bishop is in f7, which means there is no move occurring in all possible boards. As it is said in the question, rook is moved out of danger. Probability that this occurs is 0.5 and the loss in the game is black becomes stronger than now as the rook is out of danger.

If the bishop is in a2, moving the queen is allowed. White wins, as question states. Probability is again 0.5 and there is no loss for white.

If the rook is taken instead of moving the queen, again black loses the rook irrespective of where the positioned bishop is. This has a probability of 1. In this situation if bishop is in a2, king is in open check and has to move to g1 or h1, either ways white is way too stronger as it has now 0.5 probability for check mate in consequent step. If the bishop is in f7, king is not in open check and black can play at 50% chance rook b7 as queen can't take rook has 50% and in third move rook takes queen 50% giving 0.125 probability for black to gain hand.

On conclusion moving queen has 0.5 probability to win the game and 0.5 probability to lose the strong hold and give black more power.

Whereas taking rook has 0.5 probability to win in next move, and less probability that black gains more power.

This is by the way a crude analysis, for just two more consequent steps, as it is quantum chess, anything can happen as the total number of boards increases $2^n$  times for n steps.


Did Fischer really have a 180 IQ? I have read many times that Bobby Fischer had an IQ of 180. Did he really have that high of an IQ? Does anyone have proof that he was ever even tested (like a citation from an early book about him)?
Sure, Fischer was an intelligent guy, but I tend to think that someone once made up that number, and it just stuck. Lately, I have seen the same, suspiciously rounded, number given to Kasparov and Carlsen.
A 180 IQ is so rare that most people have probably never met someone, who was officially tested, with such a high IQ. Thus, maybe they just assumed it must be super high, and threw out a number. 180 is in the 99.9999712895 percentile. 140 is already considered a genius and is in the 99.3790320141 percentile.
How can one even tell by just listening to his interviews if he was that intelligent? Is there any legitimate way to prove that claim or disprove it?

From Quora: What was Bobby Fischer's IQ? (2018):

  Short answer: In 1958, when Fischer sat a Stanford-Binet test at the age of 15, his score was 180-187. But in today’s terms, Bobby Fischer’s IQ should be 148–155 on the Fifth edition of the Stanford-Binet test, and 150-160 on the WISC-V/WAIS-IV tests administered by Mensa.

The only reference provided for the 180-187 score is a link to the webpage The Mind of Bobby Fischer by Frank Brady where it states that

  In previous writings I have cited Fischer's I.Q. as in the range of 180, a very high genius. My source of information is impeccable: a highly regarded political scientist who coincidentally happened to be working in the grade adviser's office at Erasmus Hall - Bobby Fischer's high school in Brooklyn - at the time Fischer was a student there. He had the opportunity to study Fischer's personal records and there is no reason to believe his figure is inaccurate. Some critics have claimed that other teachers at Erasmus Hall at that time remember the figure to be much lower; but who the teachers are and what figures they remember have never been made clear.

The given rationales for the deflation of the score per today's standard are the Flynn effect based on a large meta-analysis that every year general intelligence increases by 1/3 IQ points, and the revised editions of the S-B test.


Given a legal chess position, is there an algorithm that gets a series of moves that lead to it? Say, given a FEN board position return a PGN move list that evaluates to it from the initial position?

The task you are considered is usually called a proof game, named such because the task is to prove that the position is legal.  As a genre of puzzles, there are various aesthetic constraints, most commonly that the resulting game be unique.  However, this is not necessary in general, and there is even a genre of counting the number of solutions.
There are several programs available that perform this task of solving proof games:

Natch is often considered the fastest.  You can see it in use in this answer to another question on this site: "Can it be proven that 11. 0-0-0+ is legal in this position?"

Euclide is apparently most useful when the sequence of moves is unique.

Popeye can solve many chess problems, including fairy chess problems.  Apparently it is not the most performant for proof games.

Jacobi is a program to solve (fairy) chess proof game problems.  It is written in JavaScript and run from browser, which makes it easy to try.

I have used Natch most successfully myself.


What is a tabiya and what is their importance? I've heard the term Tabiya used online though I've never really run into it in any chess book I've read.  I have an idea of what the term means but I'm not sure I'm correct, so first I'll say what I think it means and someone can clarify or correct me if I'm wrong.

I believe the term tabiya refers to a position that arises in an opening after a sequence of more or less standard moves from which there are multiple continuations.  That more or less I've gathered from seeing it defined online, but I believe there is a little more nuance in that the multiple possible continuations should represent distinctly different possible plans rather than just slightly different ways of trying to achieve the same plan.  So if anyone can tell me if that's correct, I'd appreciate that.

So then if that's correct, the real question is, if this is an important concept, why don't I see it mentioned much in chess literature?  Is it just because it's an obscure term and an author would probably just say something like, "From this point, White has a number of possible plans...?"

"Tabiya" is a word that came from Sanskrit and passed into Old Persian, and then to our languages. It means "battle array".

The ancestors of chess, shatranj e chaturanga, had pieces with very slow movement (for example, our "Queen", at that time called General or Advisor, could move only one square diagonally). For this reason, the opening phase of a game could be very boring, since each player had to develop pieces without really attacking the opponent. The "real" game started only when both players had pieces "close enough" to begin the battle. This "close enough" situation was called tabiya.

During the centuries, some variants of the game evolved in different ways. One lead to the "chess" we know nowadays. Another lead to some variants of Thai Chess, for example, where players use pieces with very slow movement like the original ones, but start playing directly from some well defined tabiyas and not from a standard "starting position".


What's an ideal game for teaching a new beginner? I sent my nephew a chess set for his 8th birthday. He doesn't play yet.
When my children were small, I taught them to play by working through a simple game in which each piece was introduced in turn. I made it into a story (e.g. "Now your queen is in danger! What can  we do about that?") until finally the child won the game with a checkmate (of course).
I had to make it up as we went along, but I am sure there must be some well-known games that would do the same job better, which is to say more excitingly and succinctly.
Can you suggest something suitable for a beginner's very first game? It doesn't need to cover things like en passant, pawn promotion or castling - just the very basics, to introduce the different characters and the plot.
(By "well-known", obviously I mean well-known as a teaching game, devised for the purpose of introducing a complete beginner to the very basics. It's completely irrelevant whether the game is a famous example from the history of chess, since that will mean absolutely nothing to an eight-year-old beginner playing his first game.)

I vote for the Opera Game. It showcases the very basics of strategy (controlling the center, getting the pieces developed ASAP, and attacking the king), and ends with a fantastic combination to force checkmate.

This is one of the most well-known games ever played, and it has been covered by nearly everyone online, so you can definitely find a good overview of this game in many youtube videos. If you watch a few yourself, (such as https://www.youtube.com/watch?v=MKvUQpQWie0) you should be able to present it as a story to your kid too.


Chess software for writing books I am currently converting some of my chess books into electronic format by manually copying the pgn and making notes. I have found lichess study and chessable courses to be useful in doing this. However, I would like to do this offline. Is there a software which will do this for me? I am looking at ChessX but the interface is too complicated for me to even understand if this is what I want.

If you're familiar with LaTeX (or if you're willing to learn it, which in my opinion is time well spent), there are some user-created packages which exist just for that. These are very easy to download (e.g. via with the MiKTeX Package Manager) and use.

To my knowledge, the most extensive and well-documented of these packages for creating chessboards is chessboard. As you can see in the documentation, it's highly flexible. As for chess fonts (i.e. being able to write moves with the symbol for the piece rather than the letter for the piece), there's the package chessfss. There are other packages too if ever these aren't to your liking, for example chess-problem-diagrams.


Capturing one bishop I was just looking for the best move in the position (White to move).

And I thought that capturing the bishop in green square would be the best as it controls

the open a8-h1 diagonal ,but the engine preferred the bishop in red square with an advantage over 2 points in its evaluation,

I am unable to see the reason (tactical or strategic)
 for this behavior.

1.Bxb2 and you're up a rook for a pawn.

1.Qxd1 Bxe5 and you're only up the exchange (rook vs bishop) for a pawn.


How to prepare opening for correspondence thematic tournament I like to play correspondence thematic tournaments as a way to practice/learn new openings/variations. Since they are unrated, I sometimes try wild/unusual moves to see what happens. However, I was wondering which is the best way to prepare for this kind of tournament if one wants to obtain best results (=win as many games as possible).
Thematic tournaments are those where all players start the game the same way, with a previously decided opening variation. This gives you the opportunity to study in advance the said opening. How do you do that? And how do you choose your moves?
Previously, I have taken the rather simplistic strategy of choosing the move with the highest winning percentage according to the database. But this sometimes leads you to inferior situations if you don't look to what happens in posterior moves.
Also, in correspondence games (ICCF, at least), players may use any help (books, databases, computer engines) they like in choosing their moves. So opening traps are unlikely to work.
UPDATE 20-10-2020
I am not interested in getting advice for a particular opening, but rather on the method you follow to prepare for such a tournament. Also, one of the interests of thematic tournaments is the opportunity to find and test new/unusual lines. I am also interested in the method to do this.

I’m not sure if a correspondence chess thematic tournament is the right place for learning the basics of an opening. For obtaining good results, i recommend:

Know your opening. Study all available grandmaster games, try to understand their plans. Get help by an engine, a book and/or a strong player. Be aware that the winning percentage of a line in a database is historical: The line might have been thought playable for a while, than the refutation was discovered, no one played the line since, so the winning percentage might remain high for a bad line. Don’t enter a correspondence chess thematic tournament until you have learned the opening. If you want to learn by playing, play a rapid online thematic tournament.
Prepare a new idea if possible. That’s something else than „wild moves“. And it is difficult. A lot of playable ideas have already been tried. But there are lines that have been played once and could be revived. And other moves have never been played and might prove correct. Test your ideas with some engines to see what happens. Your opponents will also use engines, so there is no need to play bad moves in a tournament just to see what happens and loosing a game by doing so. But don’t believe an engine a single word about complicated endgames ;-) That’s the reason why correspondence chess still exists in spite of engines.

While in an unrated thematic tournament, you will find players who do not respect their opponents and play „wild moves“, be kind and don’t do so. Even unrated events are taken serious by most of their participants.


How to handle the standard Bb4 (or Bg4 / Bg5 / Bb5) pin? Here are two extremely common pins, given from white's perspective for clarity:

A black bishop at g4 pinning a white knight at f3 to the white queen at d1.
A black bishop at b4 pinning a white knight at c3 to the white king at e1.

White has a few countermeasures:

Breaking the pin with Be2 or Bd2.
Breaking the pin by castling or moving the queen.
Playing a3 or h3.

The first option, while maybe not always the best move available, seems to almost never be a bad move. How should black respond?

The second option is generally good when it does not result in the bishop capturing the knight and doubling pawns. If white has broken the pin in this manner, how should black respond? Generally I capture and double pawns if possible. Otherwise I just leave the bishop there.

The third option is the trickiest. When should white "put the question to the bishop" like this? And black usually has a few replies available: retreat the bishop to a5 or h5, retreat to c5 or f5, and take the knight. How should black decide between them?

I realize that it's hard to give general guidelines here, since every chess position has unique considerations. Still, any rules of thumb would be appreciated. I would rather be right 80% of the time than fly blind and "flip a coin" on these decisions every game.

I realize that it's hard to give general guidelines here, since every chess position has unique considerations. Still, any rules of thumb would be appreciated. I would rather be right 80% of the time than fly blind and "flip a coin" on these decisions every game.

If he ignores your pin by castling / moving queen / interposing the bishop, you have 2 options : exchange or keep the bishop.

I would prefer to keep the bishop, but then you need to put pressure on pieces / squares that are connected with the pinned knight. Pressuring the center ( e4 / d4 ) is always good. This way your bishop remains useful even after White breaks the pin.

If you decide to exchange, remember that in endgame, bishop is superior to knight ( my answer to this question is instructive regarding bishop vs knight debate ).

Still, many openings ( like Nimzo-Indian ) are viable even after the exchange of bishop for a knight. Equality is reached by creating swift action by opening the game for the knights. Why? Because knights are better positioned in the early game then bishops since they are centralized in one move. while bishops need lots of maneuvering to get ideal squares.

Furthermore, by exchanging the bishop for a knight, you remove your piece that made 1 move for his piece that made 1 move, but in order to recapture he needs to play with the same piece twice while you get the chance to introduce new piece. This gives you development advantage, so it is logical to open the game.

In short, if you exchange be ready to start swift action. If this is not possible, you must get some compensation ( like better pawn structure, development advantage... ) or else White will favorably position the bishops and open the game with devastating effect.

As for "putting the question" to the bishop, again you can exchange or keep the bishop. If you exchange, then proceed as I have described above. Otherwise you can maintain the pin or reposition the bishop, but the principle is the same as above: if you can pressurize points / pieces connected with his pinned units, maintain the pin ( but always asses the consequences of g4 push! ) otherwise just reposition the bishop to a better square. He did lose a tempo and has weakened himself with h3 so you have time to play twice in the opening with the bishop.

I understand that all this might be abstract, so here are some illustrative diagrams that should help you even further:

[Title "Bishop exchange that speeds up implementation of a plan"]
[fen ""]

1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd5 exd5 5.Bg5 Be7 6.Qc2 O-O 7.e3 c6 8.Bd3 Nbd7 9.Nf3 Re8 10.O-O Nf8 11.h3 Ng6 12.Bxf6 Bxf6 13.b4! a6 14.a4

This example illustrates what to do when opponent breaks the pin -> just stay calm and play in such a way that bishop move becomes useful. Again, as I have said before, the pin usually puts pressure on the center ( here on d5 pawn ), and simply pressuring that point will justify the bishop's position even after the pin is broken. Notice how White got extra move with the exchange to start fast minority attack: without Bxf6 Black's dark square bishop would prevent this move so White would have t play a3 first in order to get b4.

[Title "Putting the question to the bishop"]
[fen ""]

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 ( 4.Bxc6 dxc6 5.O-O f6 ( 5...Bg4?! 6.h3! Bh5? 7.g4! Bg6 8.Nxe5 Bxe4 9.Re1 ) 6.d4! exd4 7.Qxd4 ) 4...Nf6 5.O-O Be7 6.Re1 b5 7.Bb3

Again a good example that shows that you don't have to exchange the bishop just because the pin becomes ineffective. This example requires explanation.

First of all, notice that it is possible to exchange the bishop, and notice how White makes swift action in view of rapid development and opening of the game. Furthermore, notice that White got compensation in view of better pawn structure ( he can create a passed pawn on the kingside, Black can't ) so this will diminish the power of bishops in the endgame. This is the application of the same principle as above.

The sideline with ...Bg4 illustrates well my warning that you must always evaluate consequences of g4 push in such positions. Black had no time to maintain the pin and should have exchanged the bishop.

Now, in the main line White was able to maintain the "pin" because ...b5 push was favorable for him ( b5 pawn is a weakness and White bishop will retreat to a good diagonal ). If you study theory of this line you will see that ...b5 move is forced because the pressure on e5 pawn is strong. Again, this confirms my principle of just putting squares / pieces that are connected with the pinned knight under pressure.

Here is an example that puts everything pretty much together:

[Title "Black applies almost all the above principles to reach a draw"]
[fen ""]

1.e4 d5 2.exd5 Qxd5 3.d4 e5 4.Be3 Nc6 5.Nf3 Bg4 6.Be2 O-O-O! 7.Nc3 Bb4 8.O-O Bxc3! 9.bxc3 Nf6!? 10.c4 Qe4 11.Bd3 Bxf3! 12.gxf3 Qh4 13.d5 Nd4!? 14.c3 Ne6! 15.dxe6 e4! 16.fxe4 Rxd3 17.Qxd3 Qg4+ 18.Kh1 Qf3+ 1/2-1/2

This example is one of the main lines in the Scandinavian defense, and is taken from the book C.Bauer-Play the Scandinavian ( 2010 ).

First crucial moment is 6.Be2. This is the moment that troubles you, right? Well, look what strongest GMs do here: they put pressure on the squares / pieces that are connected with the pinned knight ( ...O-O-O! ). This example clearly illustrates the connection between the pinned knight and the center, and why it is more important to pressure the center then to rely on a pin that will be short-lived anyway.

Now comes the second momment that illustrates second type of position that troubles you: bishop pins the knight against the king ( 7...Bb4 ). What happened here? White castled, and here we must analyze the position thoroughly so we can understand why 8...Bxc3! was played.

Black could try to move the queen and preserve the bishop, but in this opening everything revolves around development advantage. White has already finished development, has strong influence on the center and will probably force Black to relinquish the bishop pair ( these guys are deadly in open positions like the one in the game ). Black on the other hand needs one more move to finish development, and he needs to maintain the pressure on White center. Moving the queen would loosen the pressure and give White time to start regrouping for an attack. That is why Black decides to exchange the bishop -> he gets extra move so knight on g8 can enter into play, he weakens White's control over center and claims e4 square for himself and gets healthier pawn structure that diminishes power of the bishops in the endgame.

I just wanted to say that you need not fear when opponent ignores your pin by castling / moving the queen or if he breaks it by interposing the bishop -> just keep playing and put pressure on the squares / pieces connected with the pinned knight, or simply exchange and start a swift action.

The last illustrative moment starts with 11....Bxf3! and here we again see the concept of exchanging the bishop to get time for a swift action and to ruin opponent's pawn structure.

Another concept is illustrated, and I have mentioned it earlier, and that is the opening of the game in order to exploit the knight's speed over bishops. Notice how strong and well posted are Black knights, while bishops were not posted on their best squares. Notice how Black got slight initiative after 13...Nd4!?, although it was only good for a draw.

I think that these examples cover all 3 cases that troubled you, in both positions you mentioned so if you have further questions leave a comment.

Hope this helped, best regards!


Finding a Kasparov Game I remember seeing a Kasparov game, where Black played a classical bishop sacrifice. He was playing against a computer, and I'm pretty sure it was Deep Junior. I have tried to find this game, but it doesn't seem to be anywhere.

The 2003 game Kasparov-Deep Junior ) was a draw by repetition. Deep Junior played a bishop sacrifice on h2 and then forced the draw by repetition.
[Title "Garry Kasparov-Deep Junior, FIDE Man-Machine WC, New York New York USA, 1/26/2003"]
[FEN ""]
[startply "19"]

1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. cxd5 exd5 7. Nge2 Re8 8. O-O Bd6 9. a3 c6 10. Qc2 Bxh2+ 11. Kxh2 Ng4+ 12. Kg3 Qg5 13. f4 Qh5 14. Bd2 Qh2+ 15. Kf3 Qh4 16. Bxh7+ Kh8 17. Ng3 Nh2+ 18. Kf2 Ng4+ 19. Kf3 Nh2+


Why does black have an advantage here? I am studying now old Polish book "ABC Szachisty" ("ABC for Chess Player", informal translation) and the following example is given there:

[FEN ""]

1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4. Nf3 e5
5. d3 Bg4 6. Bd2 Nc6 7. Qe2 Nd4 8. Qxe5+ Qxe5+
9. Nxe5 Nxc2#

And this example is aimed to show the significance of the center. So my two questions that I don't understand here are:

Why this example satisfy its aim, i.e. shows how important the center is? My guess would be that since black figures are well centralised, they have short distance to white's position, and that is what is making mating attack possible (also white's mistake of taking the pawn). I don't understand however why control over the center is important here.

Why, after 6th move black has better control over the center?

[FEN "r3kbnr/ppp2ppp/2n5/q3p3/6b1/2NP1N2/PPPB1PPP/R2QKB1R w KQkq - 3 7"]

I see that white knight on f3 is pinned and f1 bishop is blocked. Also, white game is very passive here. However, black has only two minor pieces mobilised here and whole queen's side is not active.

First things first, this is an example of a very poorly played game, so Black gained its edge because of White's tactical mistakes, rather than by taking advantage of their extra space. This is a "fault" often made by chess authors when trying to illustrate a concept. They will explain the events in a game in a way that "fits their narrative" rather than provide an objective analysis, which is this case would lead to conclude that the position is pretty much balanced if not slightly advantageous for White until the horrible 7.Qe2.
It is true, though, that by move 6, White's lack of interest in fighting for the center costed them most of its starting advantage despite Black having lost several tempi with their queen. White could have played 7.Be2 (among others) and still have a reasonable position despite Black's lead in the center due to their extra development.


What are some of the most unsportsmanlike conducts witnessed in over-the-board play? Back when I was in high school, I played chess with a group of other students. One of the students would pick on me sometimes. Once, we decided to play and he cornered me into a forced mate in two. Before the threat turned into the final execution however, I swept my arm across the chessboard vehemently, blasting the pieces across the room. Needless to say, he got very mad. I spontaneously kept doing this for a few more games (to my sole entertainment).

Curt von Bardeleben is known as the opponent who never returned. After move 25 in the Battle of Hastings, Steinitz's opponent mysteriously disappeared:

  At this point, Steinitz's opponent left the tournament hall and never reappeared. By these offensive means he hoped to deprive Steinitz of 'a piece of immortality', ... - Art of Attack, V. Vukovic. pp 21

What are some of the most unsportsmanlike manners witnessed in over-the-board chess play?

Here are some examples of unsporting behaviour I have heard of before:

Kicking opponent under the table (from Josh Waitzkin in the Chessmaster tutorials)
(Added for interest) Running down the clock in correspondence chess with the aim of waiting for an opponent to die of old age (this shouldn't be a major issue under the ICCF, as games with deceased players are now cancelled or substitutes are called, but they could be misrecorded as a loss on time)
Using an iPhone for analysis (hat tip to @SmallChess)


For White, which variation of the Queen's Gambit Declined tends to lead to the most solid, positional, slow, closed, quiet and strategic positions? I am a 1750 Elo player with a very positional, quiet and strategic style of play.

I would like to know which variation I should play when, as White, I face the Queen's Gambit Declined.

The variation must meet these two conditions:

On average it must tend to lead to positions which are as much solid, positional, slow, closed, quiet and strategic as possible (I want nothing sharp and tactical).
I should be able to play it both by beginning with 1. d4 d5 2. c4 e6 3. Nf3 Nf6 and by beginning with 1. Nf3 d5 2. d4 Nf6 3. c4 e6

[fen "rnbqkb1r/ppp2ppp/4pn2/3p4/2PP4/5N2/PP2PPPP/RNBQKB1R w - - 1 0"]

I am hesitating between these three variations :

The 5.Bf4 variation: 4. Nc3 Be7 5. Bf4
The 5.Bg5 variation: 4. Nc3 Be7 5. Bg5
The Catalan: 4. g3

The fact that you would consider opening Nf3 suggests that you are open to openings like the Reti. The Catalan g3 leads to (somewhat) this kind of opening, albeit with a pawn on d4. More to the point, with the light squared bishop on the long diagonal, it appears to be an opening of the slow, steady, quiet variety that you favor, keeping White's strategic advantage for as long as possible, at least until you make a mistake, or Black outplays you.

The other variations, with the black-squared Bishop, do have the advantage of developing a new piece, but they are also more "tactical" and lead to earlier conflict. If I understand your question correctly, that's precisely what you want to avoid.


I lost a game without making tactical mistakes; how can I avoid this happening in the future? Here's a game of mine from last night.  It was my first tournament game for many years.

(This game is David Kenney vs. Douglas Stones [me] 1-0.  Press F to flip the board.)

[fen ""]
[Event "Bluenose Chess Club Tournament"]
[Site "Halifax"]
[Date "2013"]
[Round "1"]
[White "David Kenney"]
[Black "Douglas Stones"]
[Result "1-0"]

1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 c6 5.e3 Bd6 6.Bd3 O-O 7.O-O Nbd7 8.e4 dxe4
9.Nxe4 Nxe4 10.Bxe4 Qc7 11.Re1 Nf6 12.Bc2 Re8 13.Bg5 Nd7 14.Qd3 Nf8 15.
Rad1 b6 16.a3 Bb7 17.b4 Rac8 18.c5 Be7 19.Re4 bxc5 20.dxc5 Rcd8 21.Qe2
Rxd1+ 22.Qxd1 Rd8 23.Rd4 Rd5 24.Bxe7 Qxe7 25.Be4 Rxd4 26.Qxd4 Nd7 27.Ne5
Nxe5 28.Qxe5 Qd7 29.Qd6 Qc8 30.b5 g6 31.Bxc6 Kg7 32.Qd7 Qf8 33.Qd4+ e5 34.
Qxe5+ f6 35.Qc7+ Kh6 36.Bxb7 Qe8 37.Qf4+ Kg7 38.Qb4 Qd7 39.Bf3 Qe7 40.g3 1-0

I didn't (seem to) make any tactical blunders, yet seem to have slowly been ground down to a loss via positional play.

  Question: How can I avoid this happening in the future?

It's unclear to me how I could do that; some things spring to mind:

Aim for more tactical openings.
Gain familiarity with the usual endgame pawn structures and piece combinations in the chosen opening.
Study grandmaster games which were decided by positional play.

(Meta-comment:  This question is motivated by the specific game above, but answers should ideally be of general interest, i.e., in the some of the themes will hopefully be useful and interesting category mentioned in this meta thread.)

In this case, the answer is "gain familiarity with the standard strategical themes of the chosen opening".

Black's #1 issue in the Queen's Gambit Declined is what to do with his light-squared bishop, which if ignored can easily get stuck behind the e6 pawn and often a c6 pawn. The two standard ways to free it are

Play ...e5 to allow the bishop to move along the c8-h3 diagonal
Play ...b6 and ...c5 and place the bishop on b7

You kind of got halfway through plan #2, but once White got c5 in, your bishop had no future.

Concentrate on freeing your light-squared bishop the next time you play the Queen's Gambit Declined and you'll be much less likely to get ground down like this. This takes priority over moves like 11...Nf6 (which you just moved back two moves later anyway) and 12...Re8.


What did R.H.M. stand for? I have a number of old chess books published by R.H.M. Press. I am curious as to whether "R.H.M." are the initials of something or someone, and if so, what?

As I understand it, R.H.M. Press was the brainchild of Sidney Fried, and Burt Hochberg was the chief editor of many of the books.  Unfortunately, neither of them is still alive.  I found a short article by Hochberg in the Summer 2000 issue of Publishing Research Quarterly entitled "An imperfect visionary," which gives some interesting historical information about R.H.M. Press, but no hint of what R.H.M. might stand for, if anything.

None of the possibilities listed by The Free Dictionary looks plausible to me.

Well, let's take Random House off the table right away, as RHM Press was a division of RHM Associates of Delaware, Inc. which lists Sydney Fried as Publisher. The California Secretary of State system lists an RHM Publishing as a "Doing Business As" name for RHM Associates.

Unfortunately, No list of officers.

There's a blurb in the beginning of San Antonio 1972 (the first book RHM published) that talks a little bit about the venture, but no details. Since the most likely RHM Associates of Delaware I can find is an investment firm, I lean towards the idea the RHM name came from the folks that supplied the money to start it.


Why is this gambit also known as the Maltese Falcon Gambit? Why is the Gibbins-Wiedehagen Gambit (1.d4 Nf6 2.g4) also known as the Maltese Falcon Attack (or Gambit)? Is there any specific reason for that?

Humphrey Bogart was known to play this opening on a regular basis. Here is one of the recorded games with him playing the opening. One of Bogart's most famous movies is The Maltese Falcon, thus the Maltese Falcon Gambit or Attack.


Is there a free downloadable mini-chess program or 'chess engine'? The fascinating miniature chess  or mini-chess ' that is chess on a 6 by 6 board. I know there are tons of decent chess programs but has anyone written a decent chess program for mini-chess. Is there a free downloadable mini-chess program or 'chess engine'?

Zillions of Games isn't free, but it plays Los Alamos chess. ChessV plays 50 chess variants.  I believe Sjaak plays microchess.

ChessV
http://samiam.org/chessv/

Sjaak
http://www.eglebbk.dds.nl/program/chess-index.html


What is the best continuation for White? [FEN "4r3/pq3k2/1p4p1/2p1Qn1p/2PpN3/3P4/PP3PPP/R5K1 w - - 0 1"]

It is White to move the above position.

After Ng5 check, the Black king can go only to g8 or f8.

If the Black king goes to g8, they lose their rook. After Kf8 by Black, what is White's best move?

Best is 2.Qh8+ Ke7, after which White has a choice:

Go for 3.Qh7+ Kf6 4.Qxb7 Kxg5, when White has won a queen for a knight with a completely winning position.
Go for 3.Re1+, which is slightly more complicated but leads to a forced mate according to Stockfish:

 [FEN "4r2Q/pq2k3/1p4p1/2p2nNp/2Pp4/3P4/PP3PPP/R5K1 w - - 0 3"]

3.Re1+ Ne3 4.Qg7+ Kd6 5.Qxb7 Re7 6.Qb8+ Kc6 7.fxe3 Rb7 8.Qa8 a5 9.exd4 cxd4 10.Qc8+ Rc7 11.Re6+ Kc5 12.Qf8+ Re7 13.Qxe7#.


Online program for FEN recalculation I am looking for any online tools that can recalculate the the FEN values based on the current FEN and a given step. Are there any such tools or should I write one on my own.

I don't think this is exactly what you're looking for, but it's at least a start.

The Analysis Board at chess.com allows you to paste in a FEN, make a move, then go to the Position Setup tab and copy the FEN.


Solving the Game of Chess: Trans-Computational in Nature or No? Mathematicians have categorized chess as a trans-computational problem.  A transcomputational problem is one in which a computer would need to exceed the size of the earth in order to have the processing power to complete the theoretical problem through brute force.  Also, to solve the game of chess means that everything would have to be decided on the first move and any subsequent deviation from the 'correct line' would result in a guaranteed loss.  It is categorically different than having an engine who can win every game. Other games have been 'solved' like checkers, where the national championship has seen the exact line of play for numerous years in a row.

Also worth noting, the expression 'transcomputational' comes from Bremermann's limit - http://en.wikipedia.org/wiki/Bremermann%27s_limit - read up if you are unfamiliar.

My question is whether or not this is an accurate diagnosis?  Does the math take into account the growing sophistication of chess engines, or even computers for that matter?  Will we ever have a chess engine that can 'solve' the game of chess without exceeding the size of the earth.  I guess to simplify my question; what is the context of this mathematical limit?

Also, to solve the game of chess means that everything would have to
  be decided on the first move and any subsequent deviation from the
  'correct line' would result in a guaranteed loss.

Then this will never happen, even theoretically. Chess does not have that much instability. In many positions multiple moves are equally good. This is both obvious and has been proven (see tablebases).

Assuming now that you are just talking about "playing theoretically optimally" (if it is possible to win it wins, otherwise if it is possible to draw it draws), then it is certainly possible that a computer merely the size of the earth could play perfect chess, but it is exceedingly unlikely that a computer the size of the earth could prove that it was playing perfect chess. No one has been able to prove things about the state of a chess position except by, effectively, brute force (except for special cases where the situation is simple enough that you can reason logically about it, such as bishop and wrong rook pawn).

(The context of the mathematical limit is the number of possible chess positions, which has been estimated to be on the order of 10^43.)


Sicilian Najdorf 6. Bg5 Nbd7 line [fen ""]
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 Nbd7

1) Why 6... Nbd7 is not played by many players? Why they prefer 6... e6 only? I could not get the answer for this. Requesting experts to answer this question with detailed explanation & examples. Thanks in advance.

6.Nbd7 is played and often the lines transpose.
If Black continues to try and avoid e7-e6, his position, though solid, is less aggressive than the other lines.

Fischer said something like:

  "The Sicilian is not a defense, but rather a vicious counter-attack!"

so with 6...e6 7.f4 Black has options like 7...Qb6 entering the Poison Pawn Variation, or 7...b5 entering the Polugaevsky Variation which are considered some of the sharpest variations in chess theory.  Why spare White the worry of having to deal with either of these lines?

6...Nbd7 is playable and probably leads to equality as well but Black is delaying his counterplay if he avoids ...e6 for long.   Some issues are that Black would like to play Qc7 and then has to worry about Nd5 when if Nf6xd5 exd5 results in a favorable structure for White.


Why are there no more exhibition games between top players and computers? The 1997 match between Kasparov and Deep Blue is likely the most famous chess match in history.  This is because it was ground breaking -  for the first time ever a computer had beaten the best player in the world.

The complete history of man versus machine contests is on Wikipedia, and it suggests that people lost interest after Kramnik lost 0-4-2 to deep fritz in 2006.  Since 2007 or 2008, there has not been another serious match.

Is this just because computers are so much better now?  What about odds matches?  I know Rybka on a regular PC managed to draw a Grandmaster with white, where white was missing a rook, and black was missing a knight.  Do people just find such matches boring?

Is there just no interest in watching a player such as Magnus Carlsen vs Rybka, or is it just that the players would never agree to it?  (Or both)

There are a combination of answers to this question. I will answer in what is, in my opinion, descending importance.

It's just boring now. Initially this was a case of human pride. A few decades ago it was a commonly held belief that no computer could ever perform at the master level or beat a grand master. It quickly became apparent that this was not the case. Due to the exponentially increasing power of computer hardware and sophistication of engine development grand master after grand master fell as systems went from needing to run on specialized hardware to beat a world class player to being able to run on a modern $1500 USD laptop. Notice that the rise of the Intel Core processor seems to fit with your time frame for lack of interest.
In the developed world we have become accustomed to the fact that computers can out-perform humans in nearly any field and I think most people just accept the fact that narrow AI will eventually have a place in every field - even if most don't have the vocabulary to express the idea in that way. Narrow (or Weak) AI is artificial intelligence that has expert, human level ability in only a single thing, such as chess. Strong AI is the boogieman of the Terminator movies and the Matrix.
Because of number 1 and number 2 there is no money in it. IBM put a lot of money into the Deep Thought/Deep Blue matches for PR reasons. Now it's Watson and language. And if there is no money, who's going to agree to play?

AI has moved on to driving cars and diagnosing cancer and heart disease. Chess was only ever just a stepping stone to more important things that can make money.


Training to avoid elementary mistakes long into tournament games? I just got back from a chess tournament after around 5 years without playing tournament chess.  I did mediocre in this tournament, and I attribute it to struggling to maintain concentration after 3+ hours into a game.

I'd play a relatively decent game throughout (imperfections on both sides here or there), but lose e.g. to some simple tactic late in the game.  Something that I would ordinarily see easily, e.g. a knight fork, but was not simply looking for it late in the game.

There seems to be no point in learning openings, endgames, etc. when you end up down a bishop and end up resigning.

Question: What training exercises (drills) can we do to prevent making elementary mistakes long into tournament games?

Fatigue leads to errors of judgment. Fatigue in long games manifests as 'seeing things that aren't there' and 'not seeing things that are there." As stated before, current health status, conditions of the room, even how much sleep was gotten the night before, are factors. Actually, errors in judgment is an integral part of the game, or as one grandmaster said, "whomever makes the last mistake loses."


Maximum DTC and maximum DTZ in the endgame KRPKRP What is the maximum DTC and the maximum DTZ in the endgame KRPKRP (rook+pawn
 against rook+pawn) ?

According to longest checkmates in chess, the longest DTM (depth-to-mate) for KRP vs KRP is 112 moves, starting from this position with white to move:
[FEN "8/7P/1K5R/8/1r1k4/8/4p3/8 w - - 0 1"]

The analysis ignores the 50 move rule.
Additionally, according to the Syzygy tablebases., the maximum KRP-KRP DTZ is 122 ply.
[Title "DTZ 122 Ply"]
[FEN "8/8/8/1P3p2/8/8/2R2r2/k1K5 b - - 0 1"]


What is the physical response to a high level chess game? Chess is used as an example of how the body can be influenced purely by brain activity:

In the middle of a chess Grand Master tournament these people are maintaining blood pressure for 6 hours' running that you only see in a marathon runner

These people are going through thousands of calories per day doing nothing more than thinking

and even that:

one of these chess Grand Masters who's just taken down an opponent ... has the exact same physiology as some ... baboon on the Savanna who's just ripped the stomach open of his rival!

Also note, it's mentioned here that Fischer was

built like an olympic athlete

In terms of heart rate, breathing, energy consumption ('calories'), and other biometric indicators, what are the typical physiological responses of the human body to an important, high-level classical chess game?

European Journal of Applied Physiology studied the physiological consequences of the tension caused by playing chess in 20 male chess players, by following heart rate, heart rate variability, and respiratory variables. We observed significant increase in the heart rate (75-86 beats/min), in the ratio low frequency (LF)/high frequency (HF) of heart rate variability (1.3-3.0) and also a decrease in mean heart rate variability with no changes in HF throughout the game. These results suggest a stimulation of the sympathetic nervous system with no changes in the parasympathetic system. The respiratory exchange ratio was rather elevated (over 0.89) at the start and significantly decreased during the game (0.75 at the end), indicating that energy expenditure progressively switched from carbohydrate to lipid oxidation. The changes in substrate oxidation and the sympathetic system seem to be due to high cognitive demands and bring new insight into adaptations to mental strain.


Does this knight and rook mating pattern have a name, or has it occurred before? [fen "5k2/8/1R6/5r2/P7/1P4P1/6KP/5n2 b - - 0 40"]

With black to move, remarkably it's mate in 2 (at first glance, it looks like black may struggle to even draw).  It occurred in a recent LiChess game of mine.  It looks like the kind of position that might occur in a composed puzzle because it contains the precise material required to checkmate.

Question: Does this knight and rook mating pattern have a name, or has it occurred before?

When there's a mating pattern involving so little material (just the rook and knight, no king), I feel it might be worthwhile studying it in its own right.  The knight and rook could be on multiple other squares and still achieve essentially the same mate.

I believe that that is called “Anatasia Mate,” based on Wikipeda's testimony.

In Anastasia's mate, a knight and rook team up to trap the opposing king between the side of the board on one side and a friendly piece on the other. Often, the queen is first sacrificed along the a-file or h-file to achieve the position. This checkmate gets its name from the novel Anastasia und das Schachspiel by Johann Jakob Wilhelm Heinse.

It gives this position as an example of Anatasia mate.
[FEN "8/4N1pk/8/7R/8/8/8/8 w - - 0 1"]

Now compare it to the checkmate from your game.
[FEN "5k2/8/1R6/7r/P7/1P2n1PK/7P/8 w - - 0 1"]

Even though the White king has an extra pawn by it, I believe it to be similar enough to call it an Anatasia mate.


Is it better to reply to 1.Nf3 with ...d5 or ...b5? After 1.Nf3 I can gain space with either of 1...d5 or 1...b5. Which of these two is better?

I presume it's 1...d5, but I just want to make sure.

After 1.Nf3 the most popular answer is 1…Nf6, which is a hundred times more common than 1…b5. 1…d5 is the second most popular choice, still fifty times more likely to appear on the board than 1…b5.

Now the difference between 1…Nf6 and 1…d5 is mostly one of compatibility with the rest of your opening repertoire. 1…Nf6 is more common because the indian defences are more popular than the 1…d5 against 1.d4.

But 1…b5 is decidedly offbeat. The reason is that it doesn't immediately fight for control of the central squares. The importance of the central squares is explained in the answers to this question:
Why is the centre of the board considered important in chess?

Still, 1…b5 isn't a mistake. It has the ideas of developing the bishop to b7, making c4 impossible and maybe annoy a Nc3 in the future. If black can consolidate, the additional space on the queenside might make a difference.

The main problem from a theoretical standpoint is probably that it is rather slow: 1.Nf3 b5 2.e4 Bb7 3.Bxb5 Bxe4 4.Nc3 Bb7 5.O-O and white has quite a significant development lead.


Creating a Opening Lines Book in ' tree-like' format I came across this Opening tree graph question where a very elegant Opening tree as displayed.

Is there a way I could make a personal opening book in this format? If yes, then which software should (preferentially free) I use?
If yes, how do you handle transposition?
If no, is there some there some other efficient way of storing personal opening line ?

Clarification : Maybe by question was misleading but  I was searching for something as a tool to create a opening lines guide by manually entering the moves rather than from a database.

https://tailuge.github.io/chess-o-tron/public/openings/openingtree.html
and
https://www.openingtree.com/
both create something similar from your games on lichess.org. I do not believe they take into account opening names or transpositions.

You could draw this on paper, or you could use a online drawing software such as Lucidchart or Google Drawings.


Why is the g3 and Bg2 set up so strong vs the Dutch? Why is the g3 and Bg2 plan so strong vs the Dutch? For example, in other main openings (KID, Gruenfeld, Queen's Gambit, Queen's Indian) it's just an alternative to the "classical" systems, those with no early Kingside fianchetto. A strong one maybe, but an alternative. In the Dutch, it seems that if White wants to get an advantage in the opening he can do it only with this set up. Nf3, g3 and Bg2.

The g3 and Bg2 setup is strong defensively and strong offensively. White wants to play e4 to challenge the f5 pawn and Black's kingside white square complex. g3 and Bg2 is one of the best ways to support e4 with Nd2/c3 and Qc2 along with defending the king.


Tools to analyse weaknesses based on Lichess history Are there any tools that can find weaknesses in your games based on your Lichess history (eg, you often play a particularly bad line in a certain opening, or often fall for a certain trap), and then perhaps offers training to help rectify it?

Yes. Certainly. AimChess does exactly that. You may want to pay for it.


chess win expectancy by material difference table or calculator Houdini Chess engine is said to have a calibrated evaluation in which engine scores correlate directly with the win expectancy in the position. A +1.00 pawn advantage gives a 80% chance of winning the game against an equal opponent at blitz time control. At +2.00 the engine will win 95% of the time, and at +3.00 about 99% of the time. If the advantage is +0.50, expect to win nearly 50% of the time.

Looked around the net but couldn't find a table? Ideally I'd like to see material difference calculator where I would plug in "1 pawn and 1 knight" down.. what is my win/loss expectancy.

There is no such calculator, that's why you couldn't find any.

About Houdini: It's not a fact. They are saying roughly, Houdini evaluation is correlated with win expectancy against the same engine same hardware, in blitz time control. It doesn't have to be the same for other engines, and it's not the same for humans of course.


The move g5 in this position I would like to know what is the reason why g5 is a necessary move for Black. I now see that what I played Bd7 is horrible as it hangs a pawn on d6 after Qb4.

I cannot see why I should weaken the f5 pawn just to threaten the Queen which after Qb4 is out of danger.

I agree that f5 is irrelevant. A weakness is only a weakness if it can be exploited.

The main reason that g5 works here is that it can force the N away from f3, and then your N can go to d4 with not only a direct threat of Nxc2, which is VERY inconvenient to defend, and the more decisive threat of Nf3!. These threats are so strong that the computer thinks that Qd6 allowing Nf3 is best by two whole pawns.

It all comes down to forcing tactics that are favorable to black.

 [FEN "r1b2rk1/pp4qp/2ppn1p1/5p2/7Q/1PNP1N1P/1PP3P1/R3R1K1 b - - 0 1"]

 1... g5 2. Qb4 g4 3. hxg4 fxg4 4. Nd2 Nd4 5. Qxd6 Nf3+ $1 6. gxf3 gxf3+ 7. Kf2 Qg2+ 8. Ke3 f2 {Is crushing.}


What did I blunder at move 23? I played a game recently on chess.com, where the most detailed analysis identified a single blunder in the game -- 23. d6  The analysis given by the computer suggested that 23 Qd1 was better, with the line it gave then chasing the black knight around the board until it was captured, and freeing the Black queen rook in the process.

Myself and my opponent both like 23. d6 (well, I liked it more than he did) as it locks out the entire Black queenside for the rest of the game.  From my perspective I'm a rook and bishop up at this point, which makes it hard to me to see this as a blunder.

Could anyone perhaps point out better reasons why I should regard this move as a blunder?

[fen ""]
[Event "Let's Play!"]
[Site "Chess.com"]
[Date "2019.02.19"]
[Round "-"]
[White "postmortes"]
[Black "Glebbf"]
[Result "1-0"]
[WhiteElo "1341"]
[BlackElo "859"]
[TimeControl "1/86400"]
[EndDate "2019.02.21"]
[Termination "postmortes won by checkmate"]

1. g3 e5 2. Bg2 Nf6 3. Nc3 Bd6 4. e3 Na6 5. Nge2 O-O 6. O-O c6 7. a3 Qc7 8. b4
Re8 9. d3 c5 10. Re1 h5 11. b5 Nb8 12. Rb1 Re6 13. Bd2 c4 14. a4 cxd3 15. cxd3
a6 16. b6 Qc5 17. d4 exd4 18. exd4 Qf5 19. Nf4 Bxf4 20. Bxf4 Nc6 21. d5 Rxe1+
22. Qxe1 Nd4 23. d6 h4 24. Ne4 h3 25. Nxf6+ Qxf6 26. Qe8+ Kh7 27. Be4+ Nf5 28.
Qe7 Qg6 29. Qe5 Kg8 30. Bxf5 f6 31. Qd5+ Qf7 32. Qxf7+ Kxf7 33. a5 g6 34. Bxh3
f5 35. Re1 Kf6 36. Bf1 Kf7 37. Bc4+ Kf6 38. h4 Kg7 39. Re7+ Kf8 40. Bh6# 1-0

This may be the horizon effect at work.

I analyzed the position a bit with Lichess' Stockfish, which at depth ~20 likes 23. Rd1 (+8.0~8.5) even more than 23. Qd1 (+7.0~7.5). The idea is the same: White catches Black's knight, for an immediate material advantage (e.g. 23. Qd1 Nc2 24. Rb2 Na3 25. Qb3).

After 23. d6 on the other hand, Stockfish still gives a solid advantage of +4.0~5.0 (no human would call that "blunder" since it's still clearly winning) at depth ~20, but the following lines are rather unforcing.

A likely explanation is that in either variation there are so many defensive possibilites left (there's a lot of open space to manoeuvre!) that Stockfish is unable to find a concrete way to force mate or even only increase White's advantage substantially within its search horizon. It does of course realize that White has the much better position, which it prices at around +5.0~6.0, but that's it. In the Qd1/Rd1 line, it then simply adds the material advantage of +2.0~3.0 of that missing knight. However, it won't do the same for the queenside rook and bishop in the d6 line since it has no way to tell that these pieces are buried forever (that would require it to go deeper in its search). The engine cannot exclude that these pieces will become active again at depth 50 or something, so it still counts them in. We as humans do of course know better (one of the last cases we do).

Case in point: While writing this, the evaluation of 23. d6 increased to +6.5 at depth 30. It will most likely converge with the one of 23. Qd1 / 23. Rd1 at some point.

From a human point of view, you should not view this move as a blunder.

Update:

Depth 32 starting from the position after 22...Nd4:

1 23. Rd1 +8.4
2 23. Qd1 +7.7
3 23. Qe3 +7.1
4 23. d6 +6.9
5 ...

We're getting closer.


In the Caro-Kann Panov-Botvinnik Attack 5... e6 6. Nf3, what are the differences between 6... Be7 and 6... Bb4 ? Which one is more solid and quiet? In the Caro-Kann Panov-Botvinnik Attack 5... e6 6. Nf3, I am hesitating between 6... Be7 and 6... Bb4

  [StartPly "11"]

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

I would like to know all the differences between these two moves.

Which one of these two moves tends to lead on average to the most solid, positional, boring, strategic, slow and quiet positions?

As surprising as it sounds, 6...Bb4 is probably going to lead to the quieter game.  The reason is that with the bishop on b4, pieces will get traded off on c3.

As an example, the game Najdorf-Portisch 1-0, from 1962 shows some of these ideas.  Although the game begins as a 1. d4 game, the position transposes directly to the Panov Botvinnik.

[FEN ""]
[Event "Varna"]
[Site "Varna"]
[Date "1962"]
[EventDate "?"]
[Round "3"]
[Result "1-0"]
[White "Miguel Najdorf"]
[Black "Lajos Portisch"]
[ECO "B14"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "43"]

1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Nf3 c5 5.cxd5 Nxd5 6.e3 cxd4
7.exd4 Bb4 8.Qc2 Nc6 9.Bd3 Nxc3 10.bxc3 Nxd4 11.Nxd4 Qxd4
12.Bb5+ Ke7 13.O-O Qxc3 14.Qe2 Bd6 15.Bb2 Qa5 16.Rfd1 Rd8
17.Qh5 f6 18.Qxh7 Kf7 19.Be2 Qg5 20.Bc1 Bxh2+ 21.Kxh2 Qe5+
22.f4 1-0


Puzzle rush vs. Puzzles I'm wondering what would be, in terms of efficient fast improvement, the best training module between puzzle rush (fast calculation and pattern recognition strengthening) and traditional timeless puzzle solving (deep calculation strengthening) ?
Does one become better than the other at some specific elo range or vice-versa?
I usually focus on timeless puzzles as I feel like deep calculation is very important for serious OTB classical/rapid games but wonder if it would be more time efficient to train with puzzle rush instead.

I'd recommend starting off with traditional puzzle solving. Once you get to whatever your target range is and have a good accuracy rate (80-100%) and you can finish each of the puzzles in 45 seconds or less, move on to puzzle rush. Of course, when you get to 100 - 200 points below your target, and are accurate and quick, you could gradually start moving on to puzzle rush from the traditional puzzle solving.


Misplaced King and Queen Suppose the players misplace the position of King and Queen in a tournament game, what should the arbiter do according to the latest FIDE rules? Does the action depend on the time control/format of the tournament?
Thanks!

The action taken depends on the time control.
For standard play (each player has 60 minutes or more for all the moves) the game is cancelled and a new game started.
For rapid and blitz (i.e. each player has less than 60 minutes for all the moves) the game is cancelled and a new game started only if fewer than 10 moves have been made. If 10 or more moves have been made then the game continues with the proviso that the side(s) with misplaced king may not castle.
Note that this will remain the case when the news FIDE Laws come in to effect in July 2017.
Some references from the current (2014 - 2017) FIDE Laws of Chess:

Glossary of terms in the Laws of Chess: standard play: G3. A game where each player’s thinking time is at least 60 minutes.
Article 7.2.a. If during a game it is found that the initial position of the pieces was incorrect, the game shall be cancelled and a new game shall be played.
Appendix A Rapidplay
A.1 A ‘Rapidplay’ game is one where either all the moves must be
completed in a fixed time of more than 10 minutes but less than 60
minutes for each player; or the time allotted plus 60 times any
increment is of more than 10 minutes, but less than 60 minutes for
each player.
A.4 Otherwise [one arbiter supervising more than 3 games or arbiter not recording moves] the following apply:
a. From the initial position, once ten moves have been completed by
each player,
(1) no change can be made to the clock setting, unless the schedule of
the event would be adversely affected.
(2) no claim can be made regarding incorrect set‐up or orientation of
the chessboard. In case of incorrect king placement, castling is not
allowed. In case of incorrect rook placement, castling with this rook
is not allowed.

Appendix B. Blitz
B.1 A ‘blitz’ game’ is one where all the moves must be completed in a fixed time of 10 minutes or less for each player; or the allotted time plus 60 times any increment is 10 minutes or less.
B.4 Otherwise [one arbiter supervising more than 1 game or arbiter not recording moves], play shall be governed by the Rapidplay Laws as in Article A.4.


Knight sacrifice performed by Deep Blue against Garry Kasparov Below is the 1997 game of Deep Blue VS Garry Kasparov:

r1bqkb1r/pp1n1pp1/2p1pn1p/6N1/3P4/3B1N2/PPP2PPP/R1BQK2R w - - 0 1

The last move 7...h6? was played by Kasparov (black), after which Deep Blue played the knight sacrifice 8.Nxe6.

Wikipedia says:

  The computer is aided by having this knight sacrifice programmed into its opening book. This move had been played in a number of previous high-level games, with white achieving a huge plus score. As an indication of how far computer chess has progressed in the 20 years after this match, modern programs deprived of their opening books are able to correctly evaluate Nxe6 as strongest; but at the time this was played it was considered probable based on other programs' performance that it was only the opening book that was responsible for this choice. The compensation white gets for the material is not obvious enough for the computer to see by itself.

How would white compensate for their sacrificed knight?

History of this line is interesting. People used to think it's good for white, maybe majority still do as well as openings books do. But in correspondence database I use there are four games with Nxe6 fxe6 and black scored two wins and two draws out of four games. The wins are from 2012 and 2013. I know a lot of white players avoiding the sacrifice these days as it is easy to lose even against much weaker opposition while it doesn't even have the objective quality. Black play is easier and more obvious. I don't like White's position, I like Black here. It is too closed without direct threats for such a material investment. I know mainly the defensive plans for black here as it is in my repertoire, ok white try to play on e-file, disrupt you with Ne5 and f7 fork threat, may want to play c5 with B/Qa5+ sometimes and even b2-b4-b5 as black is undeveloped for quite some time. It is positional sacrifice and very interesting one.


Question about four digits appearing next to move As new to this as you could get i think.
Could you explain the four digit numbers that appear next to what i guess you call annotations. I would either think it should go for the highest or the lowest number, but no.

Haven't been able to google the answer, lack of imagination i guess.

Thanks for your help!

I think you are using "Lucas chess" here with Rybka. Even though Lucas chess is a real neat software, I eventually preferred the (-1 / 0 / +1) kind of representation of the evaluation. Each number next to the move is an evaluation or weight associated with the move. As you can clearly see it is considering many different moves (usually called MultiPV in UCI terms) and giving its evaluations.


How much worse would I play if I played blindfolded? Suppose I played a chess game with 60 minutes on both side. I play blindfolded while my opponent does not. Assuming that my rating is 2000 fide, what rating would my opponent have to be so that the expected score is a draw? Is this dependent on a person's rating? This question might be hard to answer. I am interested to know if anyone has any insight from their experience playing blindfolded.

I think it is ridiculous to assume that someone's normal rating would in any way be indicative of their blindfold rating. Your understanding of chess and ability to play with the chess pieces in front of you has little to do with your ability to hold all of the information in your head.

The only assumptions you can make are:

A) a person isn't going to be better at blindfold chess than they are at regular chess

B) someone with a higher rating in regular chess is more likely to be better at blindfold chess than a lower rated player.


Teaching endgame ideas to children I am looking for some advice and pointers on teaching young kids about endgame ideas. (Say for children ~8 years old). I am asking specifically regarding my nephew, but I have seen this happen to other kids as well. Often, they know how to mate with K+R vs K, K+Q vs K and similar.

In their actual games, they will get a good position (often even a piece advantage) and then they are just meandering instead of casting a mating net. Here's the interesting thing, if my nephew is shown a mate in 2 or 3, he'll usually figure it out. But in his own games, he seems happy to just keep making the moves.

Any suggestions and link/book pointers from parents, coaches welcome.

It looks like he didn't quite integrate that the point of making moves is to win the game in the end.

A piece advantage is just a means of capturing more of an advantage (often, a queen via promotion), to easily crush defenses and mate. At least, that's what I'd go for with a piece advantage. If they don't have a piece advantage yet, then try and get it¹. I wouldn't call that endgame², though.

Now, being 8 years old, I think that this will just come as he grows and thinks more in terms of goals in a fight, and less as a game where you play moves according to some rules. I don't think you should worry about that if he's happy as it is. At least, not until he starts being bugged by “and now what” himself.

This question might be of interest.

¹ I wouldn't mind making capturing pieces the first objective of a young player once he knows checkmate is how a game ends. If he loses games while being ahead in material, he'll learn the difference.
² Endgame, in my mind, is about more equal positions, how to win and not draw, or how to get an endgame advantage. I'd call finishing a game with a piece advantage “finishing the work”, rather.


Is it possible to checkmate with rook and knight against just king? I have a pawnless game with a rook, knight, and king against just a king. Can I checkmate from this position?

[FEN "8/8/8/8/1n6/8/2rk4/1K6 w - - 0 1"]

Yes, since K+R is an easy beginner checkmate.  In fact, the Knight will get in the way.  The only value of the Knight will be to get White into Zugzwang quicker (easier?), which helps Black push the king to an edge.

To answer the specific question, from above, assuming Black to move:

1... Kc3
2. Ka1 Rc1#

Assuming White to move:

1. Ka1 Kc3
2. Kb1 Kb3
3. Ka1 Rc1#


Is it good to have a tendency to exchange pieces? This is how I am playing nowadays. I can beat ~1500 player 50% of the time (the rest is due to tactical errors):

Play the opening (upto 12 moves)
Don't blunder
At the point where my pawns and pieces are in a better shape than the opponent's, I first exchange the queens
Centralise my king
Slowly exchange all the minor pieces, then the rooks
Win in the endgame

Now is this really the way to play chess? I mean, I do want to improve my tactical skills but my decision is that once I am able to beat a 1500 player 100% of the time, I will start playing tactical chess, with which I mean attacks and stuff.
Is there something wrong with my approach?

Now is this really the way to play chess?

Well, it is certainly a way to play chess. It's the way Aryan Tari chose to play Magnus Carlsen in the Altibox Norway tournament a couple of days ago. Swap as many pieces off as you can, get to a more or less equal endgame, maybe have to survive a bit of pressure then shake hands for a draw. It didn't work out that way. He got positionally crushed from a position which, to this patzer, looked fairly even.
It certainly didn't look roughly even to the chess24.com commentary team of Judit Polgar and Vladimir Kramnik. "60% lost / 40% drawn" said Kramnik, "Go back to school, Aryan" said Judit during the commentary after move 18.
After 21. Nd2:

The strategical battle is over at that point. It's very nice when you
can just follow a plan and you don't need to calculate

was Carlsen's comment afterwards.
I have to admit I have lost a fair number of games against stronger opponents like this just as I have won games against weaker players like this. The biggest difference between good players and bad players is not tactical ability (although it is often also a factor). It is the ability to accurately evaluate positions. Weaker players happily aim for bad positions because they don't know any better and stronger players can't believe their luck. Ask Magnus.
Bottom line: you are going to lose if you try and follow this plan against stronger players and if you try it against a weaker player who is weak tactically but strong positionally then you are also going to lose.
Here is the game.
[title "Carlsen - Tari, Altibox Norway Chess 2020"]
[fen ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. d3 b5 7. Bb3 d6 8. a4 Bd7 9. c3 Na5 10. Ba2 c5 11. Bg5 O-O 12. Nbd2 Rb8 13. axb5 axb5 14. Re1 b4 15. Nc4 Nxc4 16. Bxc4 bxc3 17. bxc3 Qc7 18. Qc2 Bb5 19. Bxb5 Rxb5 20. Bxf6 Bxf6 21. Nd2 Qc6 22. Qa4 Rfb8 23. Nc4 Be7 24. g3 Qc8 25. Qd1 g6 26. Kg2 Bf8 27. Qf3 Rb3 28. Rec1 Qe6 29. Ra7 R8b7 30. Rxb7 Rxb7 31. Ra1 h5 32. Ra8 Kg7 33. Ne3 Rc7 34. Nd5 Rc8 35. Ra7 Rb8 36. h3 Rd8 37. g4 hxg4 38. hxg4 Rd7 39. Ra8 f6 40. g5 f5 41. Qh3 Rf7 42. Re8 Qxe8 43. Qh6+ Kg8 44. Qxg6+ Kh8 45. Nf6 1-0


What does the †† notation mean? I am reading a book on chess openings called 51 Chess Openings for Beginners by Bruce Albertson and the author uses notation like so:

  ...†† Kxf7

What does the †† mean? I know a single † means check however the author doesn't (to my knowledge) explain what the †† is meant to signify.

EDIT: here's a screenshot to provide some context of its usage

Well, after your update I come to the conclusion that these signs are used by the author to mark the omission of the notation of the respective move by White.

This is not a common usage of them, and I have never seen it before. It should be documented somewhere at the beginning or end of the book. But I'd not be surprised  if it's not, since it doesn't reflect a healthy common sense to use the check symbol of all things for this purpose to begin with..


What is a good free interface to create and store positions? I'm getting back into chess, and I'd like a way to create and store multiple chess positions to review. Specifically, I want to review and practice mating nets. There are a ton of chess tactics sites that offer tactics training, but I want to be able to create and review specific types of positions. Does anyone have suggestions?

If you have a PGN file of those position you could use my site for that. There are already a couple of people using the site not to study openings but have uploaded PGNs of endgame positions to train.
If your PGN software specifies a starting position not inside of a "FEN" header let me know: https://github.com/ArneVogel/listudy/issues/2


Deep Rybka vs Deep Fritz vs Houdini vs (other), which one to buy? I want to invest my hard-earned money to buy a chess engine which can help me to:

analyze games easily
experiment with different opening repertoire
strategical analysis
positional play

I don't expect an answer like, all are good enough to beat a human player, etc. I am not looking for an engine whom I can beat, as I know it's not humanly possible for a 1600 rated player to beat these engines, but my purposes are different (as given above).

So, if you have or use any of these engines, please let me know a comparative detail on which one I should go for.

I would suggest you look into some open source engines. And tools for analysis.  These will be free. Some will be quite fully featured and very very powerful:

Stockfish. Rating: 3121
Critter (free) Rating: 3207

Also, look into SCID: an information database to which you can import millions of games and pair the database with analysis engines, add chess move-engines etc.
    -https://en.wikipedia.org/wiki/Shane%27s_Chess_Information_Database

note 1: there are millions (literally) of master games which have been annotated, and can be downloaded in zipped .pgn files, then which can be imported to SCID for play through etc. So analysis, openings, endgames etc, can all be analysed via scid though whichever engines you decide on (no reason to only have one).

note 2: Crafty finished in second place in the 2010 Fifth Annual ACCA Americas' Computer Chess Championships. Crafty lost only one game to the first place winner Thinker.

note 3: In various computer chess rankings Stockfish 2.1.1 was second or third behind the top gratis program Houdini and the free program Critter.

Good Luck!


An interesting eight pieces Queen endgame Looking at a human game between strong players, one of the variations reached the following endgame WHITE to move.
[FEN "4Q3/8/2pK4/1p6/1P4k1/P7/8/7q w - - 0 1"]

Since Qxc6 is a draw (Lomonosov tablebases) is the endgame a draw? Or there is a sophisticated win for White in some way, maybe submitting the black King to a barrage of checks? Since my engine does NOT have tablebases incorporated into it I am in the complete dark. What does FinalGen say about this endgame?

Stockfish with tablebases gives flat 0.00 so it seems highly likely to be a draw. A problem for White is they can't even take the c6 pawn with the king, 1.Kc7 Qh2+ 2.Kxc6 is a draw. So since Black can just keep giving checks and force the white king on awkward squares this seems hard to ever be winning. (especially since Black can always threaten to pick up the a3 pawn making an immediate draw)


What chess websites are worth subscribing to? I am a member of ICC and I find it useful although it may be a bit pricey. In a recent question about "What types or kinds of chess players are there?", chubbycantorset pointed out a video on www.chess.com by GM Kaidanov. I started watching the video(s), but realized that they only show you the first few minutes unless you sign up, so what chess websites that require a paid subscription are worth it?  This may be subjective, but I will limit worth it to mean: Quality, Community Size, Features, and Price.

Not a pay site, but FICS (free internet chess server) is my go-to for online chess.

Chesstempo is where I go for tactics and endgame puzzles (I think they have a subscription option, but I haven't subscribed, and so can't say for sure).

Playchess is associated with ChessBase and although I haven't tried their online service, ChessBase is an amazing program and good company--- they also sell video tutorials.

Utlimately, I'd recommend using the money you'd spend on a subscription on a good chess coach--- nothing beats that.


Sacrifices, initial loss and a volte-face? What is the most famous example where player was losing heavily (down on material) in the beginning with lots of sacrifices but came back strongly to beat or "pwn" their opponent?

I am not asking for weaker player beating strongly rated players. Rather someone who was creatively toying with opponent by sacrificing each and everything or playing like a looney only to reveal a method to madness. Sort of like Laurence Fishburne saying "Your son creates like Fischer." in Searching for Bobby Fischer.

Thanks!

This question might be a little too much in the discussion, no definitive answer category but I will answer anyway.

My answer would be the game known as the immortal game between Adolf Anderssen and Lionel Kieseritzky on 21 June 1851. Anderssen gave up both rooks and a bishop, then his queen, checkmating his opponent with his three remaining minor pieces.

Wikipedia's entry on the game is here

As a side note the list of games here has many games that would fall into this category, I haven't looked at them all but there are many interesting games on this list.


Queens Gambit Declined vs Slav: Exchange Variations I am a keen player of d4 as white. One of the things that I often read is that the exchange variation of the Queens Gambit Declined is generally considered good for white:

[fen ""]
1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. cxd5 exd5

But the exchange variation of the Slav (or exchanging after Nc3 in the Slav) is considered better for black:

[fen ""]
1. d4 d5 2. c4 c6 3.cxd5 (3. Nc3 Nf6 4. cxd5 cxd5) 3...cxd5

I checked http://www.chessgames.com/perl/explorer and it seems to support this view, with the following win/draw/lose statistics for white for the above variations:

QGD All Variations: (41%, 37.7%,21.3%)
QGD Exchange:  (49.8%,35.3%,14.9%)
Slav All Variations: (37.8%, 41.3%, 20.9%)
Slav (early exchange): (22.5%,55.2%,22.3%)
Slav (exchange after Nc3): (30.2%,49.9%,19.9%)

So it seems clear that the exchange of central pawns favours white in the QGD, but favours black in the Slav.

My question is simply - why? The resulting positions are superfluously similar (in the Slav black is missing the c-pawn, while in the QGD the e-pawn), yet positionally these must be very different! Is there a simple explanation of why this is the case? Would a clever newbie (i.e. somebody who plays chess very well, but have never played these variations) be able to make this deduction over the board through pure reasoning, or is this the type of thing you can only deduce by studying the opening theory?

White happens to have a couple of nice concrete plans in the particular QGD Exchange variation you mention (1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd5 exd5). One involves e3, f3, Nge2, and a break in the center with e4. The other is a minority attack on Black's a7-b7-c6-d5 pawn structure with b2-b4-b5. You will note that White's stats are much worse in the variation 1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.cxd5 exd5, even though the pawn structures are the same, because he no longer has the f3/e4 plan. So it is not nearly as simple as "the exchange of pawns favors White in the QGD but favors Black in the Slav."


Where did I go wrong? QGD loss as black [fen ""]
[Date "6/8/2018"]
[White "Anonymous"]
[Black "Me"]
[Result "1-0"]
[WhiteElo "2146"]
[BlackElo "1874"]
[Opening "Semi-Slav Defense"]

1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 e6 5. cxd5 exd5 6. Bg5 Be7 7. Qc2 h6 8. Bf4 O-O 9. e3 Nbd7 10. Bd3 Re8 11. O-O Nf8 12. a3 Ne6 13. Bg3 Bd7 14. Ne5 Bf8 15. Bh4 Be7 16. Bg3 Nf8 17. b4 a6 18. Na4 Nh5 19. Rab1 Nxg3 20. hxg3 Bf6 21. Nf3 Ne6 22. Nc5 Qc7 23. Rfc1 Ng5 24. a4 Nxf3+ 25. gxf3 g6 26. b5 axb5 27. axb5 Rab8 28. Nxd7 Qxd7 29. bxc6 bxc6 30. Rxb8 Rxb8 31. Qxc6 Qxc6 32. Rxc6 Be7 33. Rc7 Kf8 34. Ba6 Rb1+ 35. Kg2 Bd6 36. Rb7 Ra1 37. Bb5 Rc1 38. Rd7 Rb1 39. Bc6 Be7 40. Bxd5 Rb6 41. Ra7 h5 42. Ba2 f5 43. Bc4 Rc6 44. Bd5 Rd6 45. Ba2 h4 46. gxh4 Bxh4 47. Bc4 Rc6 48. Rf7+ Ke8 49. Rh7 Rxc4 50. Rxh4 Ke7 51. Rh7+ Ke6 52. Rb7 Rc6 53. Rb5 Rd6 54. Kg3 g5 55. Rb1 Kf6 56. Rb5 Ke6 57. f4 g4 58. Re5+ Kf6 59. f3 gxf3 60. Kxf3 Ra6 61. Ke2 Ra2+ 62. Kd3 Ra4 63. d5 Ra6 64. Kc4 Rd6 65. Kc5 Ra6 66. Re6+ Rxe6 67. dxe6 Kxe6 68. Kc6 1-0

My rating: 1874

My opponent's rating: 2149

Feel free to address these points or any other important bits of analysis throughout the game:

I've saw some recommendations after the game of 6...h6 7.Bh4 Bf5.
Perhaps I should play 7...O-O and Nbd7 straight away without 7...h6?
12...Ne6?! seems like it gave me some problems. Nxf7 followed by Bg6 can now be considered. What else should I be doing? Perhaps 12...a5 was better? How about 12...Bd6?
Is 14...Bf8 a waste? I wanted to open the e-file and was struggling to find a productive move.
16...Nf8: I felt that my knight was misplaced due to the concerns with white taking on f7.
Perhaps instead of 17...a6, I should be advancing on the kingside as quick as possible. Is this good thinking?
Maybe 21...h5 instead of putting the knight back on e6?
Was 27...Bc8 more stubborn? I think white could still seize control of the a-file.
After move 32, I felt that I was lost. The d5-pawn can't be held onto forever. Maybe an opposite colored bishops ending with 2 extra pawns would've been a bit more unclear than the rook ending? But I felt it was still quite winning for white.

Thanks!

I'll go through the game and address your points.

In the opening, you should have played 6...Bf5 (or 6...h6 then 7...Bf5, like you said). The reason for this is that in the Exchange QGD, your light-squared bishop is bad, while White's light-squared bishop is good. If White loses his light-squared bishop, playing the thematic b5 push of the minority attack becomes difficult. Back to the point: by developing your bishop to f5, White cannot bring his bishop to d3, or else you do the favorable exchange.
7...h6 is a very subtle mistake, for a few reasons. First, in the exchange QGD White would prefer to have his bishop on f4, not g5. The reason he doesn't play 6.Bf4 immediately is that you can answer with 6...Bd6! in one go. By playing 7...h6, you give White a "second chance" to play Bf4, and now you have to waste another move to counter with ...Bd6. The second reason 7...h6 is a mistake is that you can't play ...Ng6 in the middlegame, since the knight is not supported enough on g6 and White can just played Bxg6. In the Exchange QGD, playing ...Ng6 is very important. It's far better than ...Ne6, since it blocks White's Qc2+Bd3 battery, and also attacks White's dark-squared bishop on h4 or f4.
12...Ne6 is actually fine, given your options. After 13.Bd3, you should have played 13...g6, 14...Ng7, 15...Bf5. This is an important idea that lets you exchange light-squared bishops. Remember it, if you are only able to develop your f8-knight to e6 (normally, prefer the g6-square for the knight).
14...Bf8 is normally a good idea, but because White has 15.Bh4 it's not so good here. A better plan would be playing 14...Rc8 and 15...c5. This undermines the e5-knight's support from the d4-pawn, and exploits the White queen's position on c2.
I don't think 16...Nf8 is that bad a move, given that you wanted to play ...Nh5. Playing ...Nh5 immediately would have dropped the knight due to Nxf7 Kxf7 Bg6+.
17...a6 was absolutely fine. By playing ...a6, you force White to waste at least a tempo playing a4 (since without this move he can't play b5 now, due to ...a6). Also, if White wants to play a4 then he must protect the b4-pawn, or else you'll play ...Bxb4. So ...a6 really ends up forcing White to waste about two tempi countering it.
I like 21...h5! After playing ...h4 and exchanging everything, you end up with a queen on h4. Then, you can do a Rook lift with ...Re6 + ...Rh6, building a battery on the h-file. Another idea is even playing 21...g5!? followed by ...g4, forcing White's knight to move away, and then ...h5 and ...h4. The problem is that White can play 22.Bf5, but you can still play 22...g4 with an interesting game.
I don't like 27...Bc8 because it breaks the coordination of your Rooks. After 28.bxc6 bxc6 29.Ra1, you're facing a difficult defence. Backing up two moves, I think 25...Re7 is strong, simply protecting the d7-bishop. After 26.b5 cxb5! 27.axb5 Bxb5 28.Bxb5 axb5 29.Rxb5, your e7-rook and queen protect the b7-pawn (which is passed, to boot). Note that on 27.Nxd7 Qxd7 28.axb5, you can play 28...a5! with a dangerous passed a-pawn. This trick of side-stepping White's b5-push with ...a5 is how Karpov once tricked Korchnoi in a game.
You're right, the endgame was lost. The d5-pawn was too weak to be held on to, and then White's just up two pawns. An opposite-coloured bishop ending without rooks wouldn't have helped much. Opposite-coloured bishops are only good against two extra pawns if you can set up a blockade on the colour complex of your bishops. With all White's pawns so close together, they form a veritable armada that can keep control over the dark squares.


The illegal moves in Carlsen-Inarkiev In the first round of the World Blitz Championship in Riyadh. Magnus Carlsen played Ernesto Inarkiev and the game ended strangely.
[FEN ""]
[StartPly "53"]
[Event "World Blitz Championship"]
[Site "Riyadh KSA"]
[Date "2017-12-29"]
[Round "1"]
[White "Magnus Carlsen"]
[Black "Ernesto Inarkiev"]
[Result "1-0"]

1. e4 c5 2. a3 Nc6 3. b4 cxb4 4. axb4 Nxb4 5. d4 d5 6. c3 Nc6 7. exd5 Qxd5 8. Na3 Bf5 9. Nb5 Rc8 10. Nxa7 Nxa7 11. Rxa7 e5 12. Nf3 exd4 13. Nxd4 Bd7 14. Nb5 Qxd1+ 15. Kxd1 Bc6 16. Bd3 Bc5 17. Re1+ Ne7 18. Ba3 Bxa3 19. Rxa3 Rd8 20. Nd4 Kd7 21. Ra7 Rhe8 22. Kc2 Kc7 23. Rb1 Rb8 24. f3 Nd5 25. Nxc6 Kxc6 26. Bb5+ Kb6 27. Rxb7+ Ne3+?? {An illegal move by Inarkiev; he leaves his King in check} 28. Kd3?! {Carlsen plays on; Inarkiev now calls an arbiter}

As can be seen above, after Carlsen played 27 Rxb7+, Inarkiev made the illegal move 27...Ne3+, leaving his own king in check. At this point Carlsen could have claimed a win because of an illegal move, however, he played 28 Kd3.   At this point Inarkiev called an arbiter and claimed a win because Carlsen made an illegal move.
As far as I read the arbiter first ruled in favor of Inarkiev. Later it was offered to continue the game from the position before the illegal move on the board, i.e. after 28. Kd3 (which was lost for black), which Inarkiev declined, after which Carlsen was declared the winner.
What rules (if any) cover a situation like this?
Also I've seen claims that Inarkiev has pulled this "trick" before. If true, when and where was that?

What rules (if any) cover a situation like this?

3.10.2 of the FIDE Laws of Chess defines when a move is illegal -

  3.10.2 A move is illegal when it fails to meet the relevant requirements of Articles 3.1 – 3.9

Articles 3.1 - 3.9 basically describe the moves of the pieces. Inarkiev's move was illegal because it breached 3.9.2 -

  3.9.2 No piece can be moved that will either expose the king of the same colour to check or leave that king in check.

3.10.3 defines when a position is illegal -

  3.10.3 A position is illegal when it cannot have been reached by any series of legal moves.

After Inarkiev made his illegal move the position was illegal because his king was in check and it was not his turn. After Carlsen made his (perfectly legal) move the position was legal again because Inarkiev was in check and it was Inarkiev's turn. Inarkiev was wrong to stop the clocks and claim an illegal move. The first arbiter made a mistake. Presumably Inarkiev said that Carlsen had made an illegal move and the arbiter took his word for it without checking - very unprofessional.

Article 7.5.1 defines when an illegal move has been completed (different from "made") and what should happen next in standard play games -

  7.5.1 An illegal move is completed once the player has pressed his clock. If during a game it is found that an illegal move has been
  completed, the position immediately before the irregularity shall be
  reinstated. If the position immediately before the irregularity cannot
  be determined, the game shall continue from the last identifiable
  position prior to the irregularity. Articles 4.3 and 4.7 apply to the
  move replacing the illegal move. The game shall then continue from
  this reinstated position.

The same definition for the completion of an illegal move applies to rapid and blitz however the way the illegal move is handled is different unless certain strict conditions apply.

In blitz illegal moves are handled like this (i.e. "Competition Rules apply") only if -

  B.3.1 The Competition Rules shall apply if:
  B.3.1.1 one arbiter supervises one game and
  B.3.1.2 each game is recorded by the arbiter or his assistant and, if possible, by electronic means.

With 69 games they would need 69 or more arbiters. I don't believe they had that so according to B.4 Rapid rules apply -

  B.4 Otherwise, play shall be governed by the Rapid chess Laws as in
  Article A.2 and A.4.

The relevant article is A.4.2 -

  A.4.2 If the arbiter observes an illegal move has been completed, he
  shall declare the game lost by the player, provided the opponent has
  not made his next move. If the arbiter does not intervene, the
  opponent is entitled to claim a win, provided the opponent has not
  made his next move. However, the game is drawn if the position is such
  that the opponent cannot checkmate the player’s king by any possible
  series of legal moves. If the opponent does not claim and the arbiter
  does not intervene, the illegal move shall stand and the game shall
  continue. Once the opponent has made his next move, an illegal move
  cannot be corrected unless this is agreed by the players without
  intervention of the arbiter.

So, the sequence of events was -

Inarkiev makes an illegal move
Neither the arbiter nor Carlsen spots it and Carlsen makes a legal move.
Inarkiev incorrectly tries to claim the game.
The arbiter who deals with it incorrectly believes Inarkiev without checking and awards the game to Inarkiev.
The Chief Arbiter correctly overturns the decision and rules that Inarkiev must make a move in the position in which he made his incorrect claim.

I don't know if the Chief Arbiter did this but in his position I would also award Carlsen an extra minute on the clock in accordance with article B.2.

  B.2 The penalties mentioned in Articles 7 and 9 of the Competition
  Rules shall be one minute instead of two minutes.

EDIT: Checking on the FIDE web site I see that they have published the regulations for the World Rapid and Blitz Championships which confirm that Rapid rules apply in the case of illegal moves -

  6.14 Tournaments will be played according to the rules of the inadequate supervision of the Rapid play Laws of Chess (FIDE Handbook,
  E.I.01B Appendices, art. 1 to 4). In addition, if a player displaces
  the pieces during the game: for the first time he receives a warning
  but for the second time he will be forfeited.

EDIT2: Perhaps I should just also point out for anyone reading this after 1st Jan 2018 that FIDE are unhappy with the "one illegal move loses in rapid and blitz" rule and this is changing from 1st Jan 2018. The new rules have a new article A.4.2 -

  A.4.2

  If the arbiter observes an action taken under Article 7.5.1, 7.5.2,
  7.5.3 or 7.5.4, he shall act according to Article 7.5.5, provided the opponent has not made his next move. If the arbiter does not
  intervene, the opponent is entitled to claim, provided the opponent
  has not made his next move. If the opponent does not claim and the
  arbiter does not intervene, the illegal move shall stand and the game
  shall continue. Once the opponent has made his next move, an illegal
  move cannot be corrected unless this is agreed by the players without
  intervention of the arbiter.

This basically says that in the case of an illegal move in "unsupervised" rapid and blitz the rules regarding when an illegal move is spotted and handled remain the same (if neither the players nor the arbiter spot it and stop the game then the game continues) but the penalties are as in standard play with a time penalty and restored position in case of a first offence and losing the game in case of a second offense.


Two questions about how the en passant capture works I am still confused about the en passant rule. There are two possibilities regarding the capture itself that are not clear to me.
[FEN ""]
1. d4 d6 2. d5 c5 3. dxc6 b5 (3. c4 e5 4. dxc6)

Scenario 1: In main line shown above, is it possible to capture via en passant again after 3... b5 with the move 4. cxb7ep? In other words, is it possible to capture en passant twice with the same pawn?
Scenario 2: As shown in the given side variation, is it actually possible to capture the black’s pawn on a later move? Note that although the black pawn is still in the diagram, you must imagine that it isn’t.

En passant can only be played when the enemy pawn moves over your pawn's capture square during it's first move (moving 2 squares); so the answer to both condition 1 and 2 is no.

It is not possible for a pawn to en passant twice in a row.

My understanding is in early chess pawns could only move one space at a time, so when the 2 move rules was added they also added en passant to counterbalance the fact that you might lose a chance at capturing your opponent's pawn since he could now move over your capture square.

So, in essence, because after capturing en passant it is no longer possible for an enemy pawn to pass over your capture square, it is no longer possible for your pawn to capture en passant.

The official FIDE rules, article 1 section 3.7d states:

  A pawn attacking a square crossed by an opponent’s pawn which
  has advanced two squares in one move from its original square may
  capture this opponent’s pawn as though the latter had been moved only
  one square. This capture is only legal on the move following this
  advance and is called an ‘en passant’ capture.


Is a pawn still backward if other pieces can defend it? What exactly is a backward pawn?  Is it a pawn that can't be defended by its own pawns or if other pieces can defend it, is it still considered backwards.

As an example, in the following is e5 and d4 backwards`.

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1. e4 e5 2.Nf3 Nc6 3.Bb5 d6 4. d4

Also, if a pawn is backwards if it can't be defended by its neighboring pawns, then doesn't this mean that every pawn starts off as backwards in the initial position of the game.

According to Wikipedia:

  "...it is a pawn that is behind a pawn of the same colour on an adjacent file and that cannot be advanced without loss of material, usually the backward pawn itself. In the diagram, the black pawn on the c6-square is backward."

  "Pieces can become weak when they are devoted to protecting a backward pawn, since their obligation to defend the pawn keeps them from being deployed for other uses."

So it is still a backward pawn if it is protected by another piece. Perhaps it is protected, but now it has become a burden on a more valuable piece.

The backward pawn creates an obligation upon (and therefore decreases the value of) whatever piece is defending it. There is a penalty if the piece defending the backward pawn moves elsewhere (loss of the pawn).


How to avoid Pirc in favor of KID I like to play the King's Indian Defense (KID) and I know little to nothing about the Pirc. So, on 1.d4 I always go for 1. ... Nf6 but I don't know what to do to avoid 2.Nc3 g6 3.e4 d6 ending up in a Pirc. Do I have to change a move order somehow or there's simply no other way than studying how to tackle this Pirc position with black?

No, you cannot force white to play c4 and end up in a KID.

However, if you want to avoid the Pirc, you have several options after 1. d4 Nf6 2. Nc3.

... d5 is the most popular and you usually end up in easy to play positions. E.g. you can fianchetto your bishop to g7, attack the center with c5, etc.. You need to be prepared for the Hübsch/Blackmar-Diemer Gambit after 3. e4, but that is nothing to be afraid of.

... c5 to attack the center immediately

... e6 which can transpose into the French defense


"A knight on a rim is dim", but a knight on a corner is ... excellent? Can someone provide a collection of GM games (I'll define a collection as 5 or more games played by a GM against a GM, to be specific), where the winning side featured, at some point in the game, a knight (of the winning side) on one of the corners (a8, h8, a1, h1).

Weird request? Yes. I've seen all pieces but the knight go to a corner square. But I've heard of top level games where it has happened for some brilliant purpose, and am interested to actually see some examples.

Here is a nice one for you actually titled "Knight in the Corner": Magnus Carlsen vs Michael Adams

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1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 d5 5. a3 Bxc3 6. Qxc3 dxc4 7. Qxc4 b6 8. Bf4 Ba6 9. Qxc7 Qxc7 10. Bxc7 O-O 11. Nf3 Rc8 12. Bf4 Nbd7 13. Nd2 Rc2 14. Rb1 Rac8 15. Nb3 Bc4 16. Na1 Ba2 17. Nxc2 Bxb1 18. Na1 Nd5 19. Bd2 e5 20. e3 exd4 21. exd4 Nb8 22. f3 Nc6 23. Bc4 Rd8 24. Kf2 Bf5 25. Nb3 Be6 26. Rc1 f6 27. a4 a5 28. Bc3 Bf7 29. Nd2 Nde7 30. Bf1 Nxd4 31. Re1 Ndc6 32. Nc4 Nd5 33. Rb1 Kf8 34. Be1 Ke7 35. Kg1 Nb8 36. Bf2 Nd7 37. Re1 Kf8 38. Rd1 Ke7 39. Re1 Kf8 40. Nd6 Ne5 41. Nxf7 Kxf7 42. Rd1 Ke7 43. f4 Ng4 44. Re1 Kf8 45. Bd4 Rd6 46. h3 Nh6 47. Rd1 Nf5 48. Bf2 Ke7 49. g4 Nh6 50. f5 Nf7 51. Bg2 Nf4 52. Rxd6 Nxd6 53. Bxb6 Nc4 54. Bc5 Kd7 55. Bf1 Nxb2 56. Bb5 Kd8 57. Bb6 Ke7 58. Kh2 Nd5 59. Bxa5 Kd6 60. Bd2 Kc5 61. Kg3 Nc7 62. Be3 Kb4 63. Bd2 Kc5 64. Bc1 Nc4 65. Bxc4 Kxc4 66. Bd2 Na6 67. a5 Kb5 68. Kf3 Nc5 69. Bc3 h6 70. Ke3 Kc4 71. Bd4 Na6 72. Ke4 Nb4 73. h4 Kb5 74. Bc3 Na6 75. Kd5 Nc5 76. Bd4 Nd3 77. Ke6


Rook and knight used together within the same move - legal? This is my first question on chess beta and I don't know if I'm insane or if the cpu is broken. So I was playing chess against a CPU on the iPhone with the app 3D Chess Game, and the CPU (playing black) made an odd move.

Black to move:

White to move (one move later):

I obviously edited this to simplify it, but the basic idea is same. That is:

Black moves Rook on a8 to d8 and Knight on g8 to f6 in the same move.

Is this legal? Or is it just a bug in the system?

That's either a bug or some non standard chess variant


Purpose of Tarrasch variation in French What's the purpose of 3. Nd2 in the French opening? Does it not block the dark-squared bishop and offer space in center for black? What's the sharpest line for white in this variation?

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1. e4 e6 2. d4 d5 3. Nd2

Now I haven't played the Tarrasch, but I am considering it, as an alternative to the exchange variation, and this is what I've discovered in my limited research.

The main purpose is to support the pawn chain, if Black continues with 3. ... Nf6, as the c3 square is available for a pawn to support d4. Additionally, as a bonus, it avoids the Winawer variation of the French, without playing the advanced or exchange variations, which are easier for black at higher levels.

While it does block in the Queen's Bishop, other than the classical lines, 1. e4 e6 2.d4 d5 3. Nc3 Nf6 4. Bg5, it's not uncommon for the Queen Bishop to remain undeveloped for most of the opening.

As for which line is the sharpest, a lot depends on black's responses.