69 votes
Accepted

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, ...
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  • 806
60 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 – “...
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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 ...
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  • 1,142
33 votes

Are there any illegal positions that are difficult to spot?

Yes - the less a position looks like a real chess game, the harder it is to spot if it is illegal or not. Sometimes, retrograde analysis is needed to prove a position can be reached in a legal way. ...
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  • 23.8k
31 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 ...
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29 votes
Accepted

The illegal moves in Carlsen-Inarkiev

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 ...
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  • 74k
29 votes
Accepted

Can I hover my finger over a chess piece without touching it in a major chess tournament?

Hovering your hand over the pieces does not violate the touch-move rule, but it is bad etiquette and arguably violates the rule against annoying your opponent ("It is forbidden to distract or ...
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  • 10.2k
18 votes

Are there any illegal positions that are difficult to spot?

If we define "illegal position" as a position that cannot happen in a game using legal moves, I think that the most difficult to spot would be positions that look normal, but are impossible to achieve....
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  • 1,198
16 votes

Is this an illegal chess move?

Playing Kg2 in this position would "put your king in check" in that the black king is attacking that square already. So, no, that would be an illegal move. The fastest way to checkmate in ...
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  • 4,822
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, ...
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  • 74k
14 votes
Accepted

Touch a piece and then claim opponent's previous move was illegal

In standard play (each player has at least 60 minutes for all the moves) it makes no difference when the illegal moves is spotted the position must be restored to the one before the illegal move even ...
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  • 74k
13 votes
Accepted

FIDE rules when opponent accidentally promotes to your Queen

So if your opponent promotes a pawn to a Queen and accidentally places your Queen on the board instead of his own, can you claim a win because of an illegal move? No, you can't. There is no ...
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  • 74k
12 votes

Can a king be checked with another king when checking square is protected by the side which gives the check?

Hi David and welcome to chess.stackexchange.com. This is a common question. It's illegal to move a king into check, or to leave it in check. This includes moving a king adjacent to the opposing king....
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  • 9,378
12 votes
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Series of illegal moves in check

The answer depends on whether or not the games are being recorded. The way this is elliptically referenced in the FIDE Laws of Chess is that a distinction is made between, on the one hand, standard ...
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  • 74k
11 votes

Why is it illegal to castle with both hands?

There is a very important rule for castling with one hand. In the Fide Handbook it is rule 4.1. 4.1 Each move must be made with one hand only. The rule applies for all parts of the move, including ...
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11 votes
Accepted

Can I move a piece protecting the king if it keeps protecting on its new location?

Yes, that's legal. For example: [FEN "6k1/6r1/8/8/8/6R1/8/6K1 w - - 0 1"] [SetUp "1"] [CurrentPosition "6k1/6r1/8/8/8/8/6R1/6K1 b - - 1 1"] 1.Rg2 The rook can move along the g-file. This is known ...
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  • 15.1k
11 votes

We found out that we made an illegal move later on in the game

FIDE Laws of Chess 7.4a 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 ...
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  • 2,983
11 votes

Is blocking a check with a check an illegal move?

Yes, it is legal, since your king is no longer being attacked.
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  • 209
10 votes

Why is castling through and out of check prohibited?

I just posted an answer to this question How did castling originate? and I think it offers a missing part of the answer to this questions as well: What the rationale is, behind not being able to ...
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10 votes

Hitting the clock without moving

The rules changed in 2017 to make this an illegal move. Article 7.5 of FIDE Laws of Chess talk about illegal moves, and now Article 7.5.3 mentions this exact case: 7.5.3 If the player presses the ...
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10 votes
Accepted

Illegal promotion in FIDE blitz game?

The rules do not mention a flipped rook, nor is there any rule that says a move can be illegal due to how the piece is placed on the square. It's a legal move. That said, it's just a rook. The ...
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  • 25.8k
10 votes

Is this move illegal?

The rules governing chess are the FIDE Laws of Chess. This point is explicitly covered in Article 3: The moves of the pieces 3.9.2 No piece can be moved that will either expose the king of the same ...
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  • 74k
9 votes

Pawn promotion to queen of the other color

Promoting to a piece of the opposite color is an illegal move. Because of the touch move rule, Black must make a different legal move with that pawn, such as promoting to a Black queen. As a penalty ...
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  • 14.4k
9 votes
Accepted

Illegal Move Missed-Too Late?

The FIDE rules say this: 7.5 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 ...
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  • 364
9 votes
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Illegal move or checkmate?

It was illegal to move the queen here (and any piece in general) if that move put the king in check from another of the opponents pieces. If the player tried to move the queen here they have to put ...
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9 votes
Accepted

Can a player win if their opponent has made 2 illegal moves, but a helpmate isn't possible?

No, the game is drawn, as per article 7.5.5 of FIDE Laws of Chess (emphasis mine): 7.5.5 After the action taken under Article 7.5.1, 7.5.2, 7.5.3 or 7.5.4 for the first completed illegal move by a ...
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  • 3,433
8 votes

How to create PGN notation with wrong moves in it?

PGN files are normal text files. You can generate it to somepoint using the software and then save the file, open it in a text editor (notepad, notepad++, ...) and continue editing there.
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  • 266
8 votes

How can I use pgn-extract to remove a game from a pgn file when there is an illegal move?

pgn-extract will do exactly that if you give it an input file and say where you want the correct games to go. For instance: pgn-extract --output clean.pgn games.pgn will put only the valid games ...
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  • 1,541
7 votes

Moving king into check

It is never, ever legal to move into check. Period. No ifs, no buts. No exceptions whatsoever. That's the best way to think about it, since it gives the least scope for confusion. If you want to ...
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7 votes

Can a king be checked with another king when checking square is protected by the side which gives the check?

This is an illegal move. Even if the White King is protected, you can never put your King en prise. However, if you were to play such a move and your opponent didn't call it ON THAT MOVE, an ...
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