Is it possible for a triple check in regular chess?

I will show by contradiction.

I am a maths-PhD student, so I feel qualified to engage in such mathematical arguments.

Assume you can give triple check. This implies that three independent pieces are attacking the opponent's king.

The only way for this to happen is if one pieces moves, resulting in a triple check. This is not possible as if, say, the knight moves and attacks the king with a check (optimal piece to use for the discovery - why?) then it would have to free up two OTHER pieces to attack the king. If it moved and two OTHER pieces did attack the king this would imply they were on the same same square. Not possible thus assumption is false.

@Burrower I will show by contradiction. I am a maths-PhD student, so I feel qualified to engage in such mathematical arguments. Assume you can give triple check. This implies that three independent pieces are attacking the opponent's king. The only way for this to happen is if one pieces moves, resulting in a triple check. This is not possible as if, say, the knight moves and attacks the king with a check (optimal piece to use for the discovery - why?) then it would have to free up two OTHER pieces to attack the king. If it moved and two OTHER pieces did attack the king this would imply they were on the same same square. Not possible thus assumption is false.

nayf edited

#32

@TaoistBurrower

"If it moved and two OTHER pieces did attack the king this would imply they were on the same same square. Not possible thus assumption is false. "

It is sheer nonsense to claim that if two other pieces were attacking a king they would have to be on the same square. In fact 16 pieces can attack a king simultaneously from 16 different squares.

I already furnished a complete proof in #7, #17, and formally in #27, but feel free to ignore it and spout nonsense.

@TaoistBurrower "If it moved and two OTHER pieces did attack the king this would imply they were on the same same square. Not possible thus assumption is false. " It is sheer nonsense to claim that if two other pieces were attacking a king they would have to be on the same square. In fact 16 pieces can attack a king simultaneously from 16 different squares. I already furnished a complete proof in #7, #17, and formally in #27, but feel free to ignore it and spout nonsense.

Timegod

#33

Its POSSIBLE because illegal positions are allowed in chess games if they are not claimed. Period end of story.

#4 stands firmly.

Yes #4 is obviously the correct conclusion, but the real challenge is explaining why.

CM Sarg0n

#36

Is it possible to promote to a bottle of beer? Yes, if one player does so and they continue to play and sign the score-sheets than it it possible.

Then everything is "possible".

Is it possible to promote to a bottle of beer? Yes, if one player does so and they continue to play and sign the score-sheets than it it possible. Then everything is "possible".

nayf

#37

@Sarg0n

Good point. That is adequate to deal with the not very serious claims about agreeing to violate rules. But explaining the impossibility of triple check is different. It is not a violation of any specific rule, as promotion to beer would be. Yet it does derive in a more complex way from various rules and geometric facts, as I've shown.

@Sarg0n Good point. That is adequate to deal with the not very serious claims about agreeing to violate rules. But explaining the impossibility of triple check is different. It is not a violation of any specific rule, as promotion to beer would be. Yet it does derive in a more complex way from various rules and geometric facts, as I've shown.

h2b2

#38

A sister question I know the answer to mainly because I've seen it mentioned in videos, not because I've thought about it and proved it right.

You can get out of a single check by moving another piece to block the check, or by moving your king.
Is moving your king the only way to get out of a double check?

A sister question I know the answer to mainly because I've seen it mentioned in videos, not because I've thought about it and proved it right. You can get out of a single check by moving another piece to block the check, or by moving your king. Is moving your king the only way to get out of a double check?

CM Sarg0n

#39

@h2b2

Try to think yourself: how to block two different attacking lanes with one piece?

@h2b2 Try to think yourself: how to block two different attacking lanes with one piece?

nayf

#40

@h2b2

It's well known; that's why a double check is normally 'safe', as it's typically a free tempo: K must move. BUT: there is also the special case of a checked K moving and discovering a return check, which can occur even after a double check. Games have occasionally been lost this way. That is why I said the double check is 'normally' safe for the player delivering it. The K always has to move. But it is not always safe or a free tempo, if the K's movement results in a discovered check.

@h2b2 It's well known; that's why a double check is normally 'safe', as it's typically a free tempo: K must move. BUT: there is also the special case of a checked K moving and discovering a return check, which can occur even after a double check. Games have occasionally been lost this way. That is why I said the double check is 'normally' safe for the player delivering it. The K always has to move. But it is not always safe or a free tempo, if the K's movement results in a discovered check.

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