63

The official procedure to castle is (Schiller 2003:19–20 from Wikipedia): first move the king with one hand and then move the rook with the same hand. By using both hands the player can save time, as would by as using different hands for moving (like promoting a pawn to queen) or moving with a hand and hitting the clock with the other.


57

Disclaimer: this is probably not the answer, but it makes for interesting thinking. This reminds me of a string bet in poker. String bets are illegal, because they can be used to gain information – “I’ll see your $5”… < watches opponent’s face> "… and raise you $20”. By moving the king first, you are making what would otherwise be ...


42

Executive summary: Black actually can castle, but if he does castle he will lose the knight and the game (due to material loss). Detailed answer: Black and White have equal material. The black knight is protected by two pieces: the king and the queen. The black knight is attacked by two pieces: the queen and rook. If the king castles, the knight will ...


37

I'm pretty sure Stockfish doesn't have explicit code that handles opposite-side castling. What it does have is: Some kind of "menace" score for enemy pawns advancing against our king. The closer they get, the more dangerous Stockfish thinks they are. Some kind of "pawn shield" score for friendly pawns in front of our king. The fewer ...


34

I know in general the rules say the hand you move your piece with has to be the one that hits the clock. If you castled with two hands which one would you use to hit the clock? This might be part of the reason for the rule saying you can only castle with 1 hand.


32

Castling is extremely useful in almost all games. It lets you do two things at once. First, it moves your king from the center to the side of the board, where it is much more difficult to attack for the opponent. Second, it brings one of your rooks towards the center of the board, and it crucial in bringing both of your rook into the game. There may be a ...


31

Chess rules are all about sequence. If you use two hands, you don't know which happened first. So you always use one hand. First, you make your move, then you hit the clock. As others have pointed out, the rook move alone could be one or two moves. Maybe, you were just moving your rook, maybe you were castling. The King move, however, does determine ...


30

If you are prepared to use standard Linux command-line tools like wc and grep then I think my free PGN processor, pgn-extract, will do much of the pre-processing necessary to count games in each category. Below is a basic bash script I put together as a proof of concept. It assumes your file of games is called inputfile.pgn - adjust as necessary, or pass it ...


26

It would certainly allow for more attacks due to kings being stuck in the center, but fundamentally changing the game, which in a way dumbs it down, is not good. It would be less complex. I also do not want to think that I spent 40 years of my life studying something only to have it changed. I do not want the rug pulled out from under me like that.


23

I can think of two questions you might be meaning to ask, given the wording of your question. Maybe neither of these is what you're after, but just in case: 1. Is it possible to castle out of check or even checkmate? Here the answer is no. If your king is in check, then castling is not a legal move. 2. Is it possible to castle while checkmating your ...


22

This is actually a rather typical retrograde problem, just start with the most basic observations: We see that black is missing both rooks and the f8 bishop. Given black's pawn structure it's easy to see that neither the f8 bishop nor the a8 rook could have escaped the structure, thus they must have been captured on the 8th row (by a white knight for ...


21

One rationale that I can think of for not allowing the king to move through check parallels that behind the possibility of capturing en passant after a pawn makes a two-square advance. The typical pawn move is just a single square forward, and the possibility of advancing two squares on a pawn's first move was a relatively late addition to the game in ...


20

Ok after playing around with a couple of lines, I finally found one line that shows it's still perfectly legal to play long castles for white at move 11, here it is: [Title "possible 11.O-O-O+"] [StartFlipped "0"] [fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"] 1.e4 e5 2.Nf3 Nc6 3.c4 Rb8 4.d4 exd4 5.Nxd4 Bc5 6.Nxc6 dxc6 (6... bxc6 7.Be3 d6 ...


20

It'll depend on the rest of the position. If it's relatively open, chances are you can keep the opponent's king in the center and launch an attack. This might well be a decisive advantage; preventing castling on both sides can be much harder than just one side or none at all. It's worth noting that 'artificial' castling (e.g. Ke8-f7, Rh8-e8 and Kf7-g8) ...


20

Unless this is a trick question, I'd say never: 3.8.2 [] This is a move of the king and either rook of the same colour along the player’s first rank, counting as a single move of the king and executed as follows: the king is transferred from its original square two squares towards the rook on its original square, then that rook is transferred to the square ...


19

The answer is plain and simple: You cannot castle twice without breaking the rules. The only chance for this thing to happen is that the illegal move (the second castling) stays unnoticed until the game is ended with an accepted outcome.


18

I suppose what is comes down to is that the way 3.8.2 is written can be argued to have a syntactic ambiguity. 3.8.2 can mean either "This is a move of the king, and either rook of the same colour, along the player’s first rank," or "This is a move of the king and either rook of the same colour along the player’s first rank." There's no ...


17

The FIDE Laws of Chess actually cover this with a recommendation without mentioning the problem. II.3.2.5.1 When castling on a physical board with a human player, it is recommended that the king be moved outside the playing surface next to his final position, the rook then be moved from its starting position to its final position, and then the king ...


16

Is there any glaring flaw in this rules lawyer case, or is it solid until FIDE fixes it? Yes, there is a glaring flaw in your case. The rook and king have to be on the same rank. This is clear from the text of the rule and the diagrams which follow. Here is the text from the latest FIDE Laws of Chess: 3.8.2 by ‘castling’. This is a move of the king and ...


16

Interesting question. I think it depends on how much bottom-up intelligence the engine has. For example, AlphaZero was given no explicit heuristics, but was able to infer plenty of strategy by playing itself millions of times and learning that way. An engine with explicit heuristics can also exhibit additional strategies you didn't program into it. As a non-...


15

Weaknesses like doubled/tripled pawn structure, color complex holes, and right to castle only matter in chess to the extent to which the opponent can exploit them. In the Old Indian variation you gave above, yes, Black lost the right to castle, but is White in any real position to exploit it? The answer is no. In fact, Black's king is very safe after he ...


15

Yes, of course he can; you're indeed in check. Imagine if checks didn't exist--then on the next move, if your king hasn't moved, he could just take your king with his rook.


15

why is it illegal to castle with both hands? Because the rules say so. From the FIDE Laws of Chess - 7.5.4 If a player uses two hands to make a single move (for example in case of castling, capturing or promotion) and pressed the clock, it shall be considered and penalized as if an illegal move.


15

I have no real preference either way, but I'll point out that Kramnik based his argument on AlphaZero playing against itself. Because of AlphaZero's style, it might not be the case that these no-castling games end up in complicated positions more often. Here're two more games to add using the no-castling rule, played in the TCEC viewer-submitted opening ...


14

The way I always understood castling is that it allows the player to move his king to safety. But this privilege does not come for free - it comes at the cost of a tempo. If a player was allowed to castle out of check, or over a checked square, then it allows him to postpone this powerful move until the very latest, effectively removing the penalty from the ...


14

Excellent question. The rules state that this is not possible. Castling can only be done once. This is explicitly mentioned under Guidelines II. Chess960 Rules: II.3.1 Chess960 allows each player to castle once per game, a move by potentially both the king and rook in a single move. [...] Specifically, castling (even if the king doesn't move) should still ...


13

The castling notation was invented by Johann Allgaier and used for the first time in his 1811 2nd edition of his Neue theoretisch-praktische Anweisung zum Schachspiel. He didn't explain why he came up with it. Allgaier (and algebraic notation in general) used digit-0. The use of letter-O is an anglo-saxon oddity.


13

A basic rule (and not just in chess): options are good. Suppose your opponent has the option of castling. If they are in a position where castling is good, they will do so. If they are in a situation where it's bad, they won't (presumably, and you should be wary of planning your strategy around your opponent making mistakes). So unless there's absolutely no ...


13

In this famous problem by H. Hultberg (1944), the white king castles to prevent Black from castling: [FEN "r3k2/1p1p2p1/2pP3p/8/8/5R2/PPPP4/4K2R - - - 0 0 "] White to mate in two moves. According to chess problem conventions, castling is presumed to be legal unless it's provably illegal. In this position, you can prove that at least one player has ...


13

This answer will focus on chess as it is played, rather than subdomains like composition or engine development. Castling is a move that usually accomplishes at least one of two things: It gets the king to safety. It develops the rook. Or both, in just one move. As castling stands now, it requires one move to reach a position that would otherwise take ...


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