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77 votes
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Why is it illegal to castle with both hands?

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, ...
Bernat's user avatar
  • 886
65 votes

Why is it illegal to castle with both hands?

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 – “...
Mawg's user avatar
  • 783
53 votes

Was AlphaZero taught castling?

Other answers are right in that AlphaZero was implicitly told that castling is a move that exists, I'll elaborate on how exactly that happens by explaining the inputs and outputs of the neural network....
KarelPeeters's user avatar
  • 1,014
50 votes

Was AlphaZero taught castling?

was AlphaZero just given this move It was given this move in the same way that it was given all other moves. It started with complete knowledge of the rules of the game. In machine learning terms, ...
Cleveland's user avatar
  • 7,584
42 votes
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Why can't the king castle in this position?

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 ...
Yaron's user avatar
  • 1,010
42 votes
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Has O-O ever been played without moving the e or g pawns?

This CQL query: cql(input Mega_Database_2022.pgn) flipcolor { { move from K o-o Pg2 Pe2 } or { move from K o-o-o Pb2 Pd2 } } returns 224 (!) games when ...
double-beep's user avatar
  • 4,350
38 votes
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Should a chess engine be aware of opposite-side castling?

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 ...
Allure's user avatar
  • 27.7k
34 votes

Why is it illegal to castle with both hands?

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 ...
Hockeyfan19's user avatar
  • 1,132
32 votes

Why is it illegal to castle with both hands?

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 ...
Guy Schalnat's user avatar
32 votes
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How often does castling occur in grandmaster games?

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 ...
kentdjb's user avatar
  • 1,806
26 votes

What are pros and cons around banning castling?

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 ...
PhishMaster's user avatar
  • 32.6k
23 votes

When is it legal to castle moving the rook first?

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 ...
Glorfindel's user avatar
  • 24.9k
21 votes
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Prove that White is not allowed to castle here

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 ...
Ellie's user avatar
  • 12k
21 votes

Is preventing an opponent from castling considered an advantage?

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 ...
Glorfindel's user avatar
  • 24.9k
21 votes
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How is white allowed to castle 0-0-0 in this position?

You can not castle if your king would start, move through or end in check. For short castling that amounts to the same, since the corresponding squares e1, f1 and g1 include all the squares between ...
koedem's user avatar
  • 3,451
20 votes
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Does a loophole still exist in the defintion of castling?

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,...
Tanner Swett's user avatar
19 votes

Is castling possible with a pawn promoted to a rook?

This question really needs a diagram with this position: [FEN "8/8/4P3/3p4/2p3p1/1pP1kPPp/1P5P/R3K2R w KQkq - 0 1"] White to mate in 3. Tim Krabbé and Max Pam found the loophole in the rules that ...
RemcoGerlich's user avatar
  • 28.1k
19 votes
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How can you castle legally in Chess960 when the castling rook is on the king's destination square?

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 ...
Brian Towers's user avatar
  • 98.1k
19 votes
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Can you castle twice in Chess960?

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 ...
NoseKnowsAll's user avatar
  • 5,793
16 votes

Why are the symbols 0-0 and 0-0-0 used for castling in algebraic notation?

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 ...
Queeg's user avatar
  • 684
16 votes

Does a loophole still exist in the defintion of castling?

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 ...
Brian Towers's user avatar
  • 98.1k
16 votes

Should a chess engine be aware of opposite-side castling?

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 ...
Inertial Ignorance's user avatar
15 votes
Accepted

Is castling possible with a pawn promoted to a rook?

No, according to FIDE's Laws of Chess, castling has to be done along the first rank. §3.8.2: 3.8.2 by ‘castling’. This is a move of the king and either rook of the same colour along the player’s ...
Dag Oskar Madsen's user avatar
15 votes

Why is it illegal to castle with both hands?

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, ...
Brian Towers's user avatar
  • 98.1k
15 votes

What are pros and cons around banning castling?

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-...
Allure's user avatar
  • 27.7k
14 votes
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Why is castling seen as making the king so safe?

The f7 pawn is really only a concern for beginners. It is not easy to attack for white with many pieces and is easily defended. Generally (in the opening/middlegame) you want to surround your king ...
user1583209's user avatar
  • 20.8k
13 votes

Is preventing an opponent from castling considered an advantage?

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 ...
Acccumulation's user avatar
13 votes
Accepted

Using the king to prevent castling

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. ...
bof's user avatar
  • 3,822
13 votes
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Why is Apronus allowing the White king to castle through an attacked square?

I happen to be the author of the chessboard editor under discussion. Let me clarify the issue. This editor is supposed to enforce legal moves but it has a bug which prevents it from being able to ...
MichalRyszardWojcik's user avatar
13 votes

How can you castle legally in Chess960 when the castling rook is on the king's destination square?

Touch your king, then your rook. By rule 4.4.1, you are now required to castle. You can now move the king and rook to their proper squares however you like, since you are already forced into a ...
Brilliand's user avatar
  • 349

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