Questions tagged [illegal-move]

A move that doesn't respect the rules of chess.

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5 votes
2 answers

Is this move valid in the rollerball chess variant?

Can the white King move a space to the right, into the original location of the black king? This would be disallowed in standard chess, as one cannot intentionally put themselves into check. However, ...
user4577's user avatar
2 votes
2 answers

Illegal move or forfeit on time - who wins this 5-minute match?

In a 5-minute match a player makes an illegal move leaving his king in a check position. This usually gives the victory to the opponent, if he sees it and captures the king. Otherwise, if the opponent ...
Philip's user avatar
  • 29
2 votes
2 answers

What are the official rules if your opponent makes an illegal move?

I heard that they lose some time or that they lose the game. I'm not sure what happens.
CognisMantis's user avatar
  • 5,011
27 votes
4 answers

Why is castling through and out of check prohibited?

Why is castling disallowed when the king is in check or when the square the rook will be placed on is under attack? What is the rationale behind this ruling?
Alexandros's user avatar
13 votes
5 answers

Hitting the clock without moving

In an official blitz game, what happens if a player hits a chess clock without making a move? I believe that making an illegal move in a blitz game is an automatic loss. But does this count as an ...
MyronL's user avatar
  • 131
9 votes
2 answers

What "double moves" are sometimes considered legal?

As we know, castling is a legal "double move," where two pieces are moved at once. But in my country, Indonesia, in my childhood, the opening below was an 'assumed legal' double move to counter 1.e4 ...
Ahmad Azwar Anas's user avatar
22 votes
1 answer

Why is it illegal to move into check?

In chess, it is against the rules to move into check, or to not move out of check. But why? Obviously, if you went against this rule, you'd immediately lose. But it seems strange to make it illegal to ...
Winston Ewert's user avatar
54 votes
3 answers

Can a piece pinned to my king put the opponent's king in check?

I was playing a game with a friend online. A situation came up where he put me in check with his bishop, and I moved my rook to block it. His king was on the g file and my rook was on g2. The website ...
ken's user avatar
  • 551
5 votes
1 answer

Why isn't the active color allowed to be in check in a FEN legal position?

The title says it. Reading up on how to describe the position of a board, all of the requirements make sense (like two kings not being on adjacent squares and so on) except for the active color being ...
Fixed Point's user avatar
23 votes
7 answers

How do you know when a FEN position is legal?

I am making a research on validating FEN positions, at first it is obvious the basics things to look for, such as checking if there are only two kings and making sure the rows or columns add up and ...
ajax333221's user avatar
  • 3,138
36 votes
2 answers

Is taking the opponent's king an illegal move?

In competition blitz games, making an illegal move and then pressing the clock forfeits the game if the opponent claims the illegal move as long as they do not make a new move, as a new move would ...
Pep's user avatar
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43 votes
2 answers

I made an illegal move. What happens?

Especially in blitz or bullet games, it is possible that a player makes an illegal move, for example castles through check. If the opponent does notice the illegal move, then as far as I know the ...
Armen Tsirunyan's user avatar