A case of carrying on past checkmate

[Anthony Appleyard]

A few days ago I was playing chess with a friend. His king was on the edge of the board. I checkmated him with my queen guarded by my knight. He, feeling tired, played KxQ, leaving himself in check. I also felt a bit tired, and played NxK and claimed win.

[MSoszynski]

I recall walking up to the bottom board of a match from the lowest division of the Birmingham League. Two old men were playing, intensely studying the position in silence except for the sound of the clock. I wondered what complications they had been analysing for so long. Actually, there was checkmate on the board. So they could still be there now.

[Alex Holowczak]

A few days ago I was playing chess with a friend. His king was on the edge of the board. I checkmated him with my queen guarded by my knight. He, feeling tired, played KxQ, leaving himself in check. I also felt a bit tired, and played NxK and claimed win.

Let's suppose this happened in a blitz game.

Suppose you played NxK and pressed the clock, and your opponent immediately claimed the game because you completed an illegal move.

I think the decision would be that you'd still win the game, because checkmate immediately ended the game, and therefore the subsequent illegal moves could never have happened. There's no law in the Appendix that overrides the "checkmate immediately ends the game" bit of the Laws.

An interesting question for an arbiters' exam!

[Clive Blackburn]

I think the decision would be that you'd still win the game, because checkmate immediately ended the game, and therefore the subsequent illegal moves could never have happened.

I wonder how long you can wait before making the claim? Supposing that there was a mate on the board in a blitz game but both players missed it and play continued. If the player who carried out the mate later realised what had happened, could he then claim it 10 moves later (assuming that he has been keeping score the whole time).

[Alex Holowczak]

I think the decision would be that you'd still win the game, because checkmate immediately ended the game, and therefore the subsequent illegal moves could never have happened.

I wonder how long you can wait before making the claim? Supposing that there was a mate on the board in a blitz game but both players missed it and play continued. If the player who carried out the mate later realised what had happened, could he then claim it 10 moves later (assuming that he has been keeping score the whole time).

If the moves are written down, there'd never be any problem at all in going back to the scoresheet. That's highly unlikely in blitz though!

1.2 [...] Leaving one’s own king under attack, exposing one’s own king to attack and also ’capturing’ the opponent’s king are not allowed. [...]

If the King isn't on the board, you could ask the non-claimant where it went missing. I can't think of an obvious answer to that question that isn't "Because it was captured." Why was it captured? I reckon the story of what happened can easily be pieced together such that a win for the player who checkmated his opponent could be awarded. Worth trying to talk some sense into said players afterwards though.

It's an interesting question. On a related theme, if a mobile phone goes off in an arbiterless match. There's no claim to be made according to the Laws - when the phone goes off, the game ends when the phone makes a noise. So if you play on for 20 moves, can you then "claim" the win if your position looks a bit dicey?

[Anthony Appleyard]

It could be said that capturing the king is something that never gets a chance to happen, rather then something specifically forbidden.

Likely, way back at the beginnings of chess in early 6th-century northwest India, the game did go on to capturing the King, but there was something semi-divine about (living human) kings, and a king dying in a boardgame seemed wrong, so the game soon started to end a move before that.

[Alex Holowczak]

It could be said that capturing the king is something that never gets a chance to happen, rather then something specifically forbidden.

It couldn't, because 1.2 does specifically forbid it: "’capturing’ the opponent’s king [is] not allowed"

Suppose in a blitz game, I put your King in check. You don't get out of check, an illegal move. You press your clock. Rather than claiming the game, I capture your King, and press my clock. You claim the game because of an illegal move.

Without 1.2 forbidding capturing the King, there's nowhere else in the Laws that forbids me from doing so, so you would have to play on Kingless, because you couldn't claim that I made an illegal move.

[Anthony Appleyard]

Sorry.

[Alex Holowczak]

Sorry.

You don't need to apologise; just pointing out the vagaries of the Laws.