Is this an illegal move?

[Chris Goodall]

3r1k1r/2p2pp1/1qb5/1p3B1P/p4pP1/2PP4/3B3K/R2Q1R2 b - - 0 1
Rapidplay game. Black has just checked White's king onto the h-file, and now plays ...g5.

Seeing that the intended hxg6 is now illegal, White captures the other way with Bxg6!! That is, he plays the bishop to g6, removes the g5-pawn from the board, and presses the clock.

Black claims: You can't do en passant with a bishop. White has made an illegal move, and so loses the game [EDIT - and so gets a warning and a 2-minute penalty.]
White claims: There is nothing illegal about Bg6. The irregularity that occurred was disturbing the g5-pawn from its square, for which the correct remedy is to restart my clock until I've replaced the pawn.

[John Upham]

I might be falling for something but here goes:

Assuming Black played ...g7-g5 and pressed his / her clock then to follow

Bg6 is a legal move and Bxg6 is not a legal move.

I must be missing something obvious for which I apologise.

[Roger Lancaster]

I might be falling for something but here goes:

Assuming Black played ...g7-g5 and pressed his / her clock then to follow

Bg6 is a legal move and Bxg6 is not a legal move.

I must be missing something obvious for which I apologise.

That's an odd one. I suppose I'd reluctantly agree that, since the g-pawn couldn't be legally captured in any way after ...g7-g5, removing it from the board had no more and no less significance than the incorrect removal of any other (immune from capture) Black unit - for which an arbiter might impose a penalty for annoying/distracting an opponent or something similar but no more. Then the move Bg6, as opposed to Bxg6, is allowed to stand.

[IM Jack Rudd]

I'd rule that white has made an illegal move, award black two minutes, and insist that white plays Bf5-g6 without removing the pawn from g5, and that a further illegal move from white will lose the game.

[Chris Goodall]

I might be falling for something but here goes:

Assuming Black played ...g7-g5 and pressed his / her clock then to follow

Bg6 is a legal move and Bxg6 is not a legal move.

I must be missing something obvious for which I apologise.

Bxg6 is definitely not a legal move, the question I'm interested in is whether it ought to be punished as an il-legal move, or as an irregularity equivalent to knocking the pawn off the board.

[IM Jack Rudd]

Illegal move, because he has deliberately removed the pawn from the board.

[Angus French]

I'd rule that white has made an illegal move, award black two minutes, and insist that white plays Bf5-g6 without removing the pawn from g5, and that a further illegal move from white will lose the game.

Also, just to point out that a single illegal move in rapidplay doesn't, as black claimed in the opening post, lose the game - it used to but it doesn't under the current 2018 laws.

[Chris Goodall]

I'd rule that white has made an illegal move, award black two minutes, and insist that white plays Bf5-g6 without removing the pawn from g5, and that a further illegal move from white will lose the game.

Also, just to point out that a single illegal move in rapidplay doesn't, as black claimed in the opening post, lose the game - it used to but it doesn't under the current 2018 laws.

Edited. You're right, that's me not paying attention to law changes.

[Joey Stewart]

Years ago I played an absolute clown in coventry called Fernando Montes who actually did make an en passant capture with a knight and swore blind that it was the rules of chess and I shouldn't be playing if I didn't know the rules properly. Needless to say I had the last laugh since he was also a terrible player and went on to lose badly .

[Chris Goodall]

Illegal move, because he has deliberately removed the pawn from the board.

Do you think that deliberate removal of a piece from the board, other than as a result of a legal capture, could usefully be added to the actions "treated and punished as an illegal move" under Article 7, or do you think Article 3 is enough to classify it as illegal?

[Christopher Kreuzer]

Some of this comes down to the way en passent captures are played on the board.

I've seen people start this capture by moving the overly advanced pawn back one square and then capturing it with the pawn. This can be slightly ambiguous if another piece can capture the pawn in its advanced state. By releasing the opponent's pawn on its less advanced square (the terminology needs improving here) that makes clear you are intending to capture en passent.

I've also seen people move the pawn diagonally as the starting point of the move, and this is more normal as it is unambiguous (though there is room for some slight confusion if there is a pawn on the other adjacent file that could be captured this way, even if that would be an illegal move - stranger things have happened in blitz).

In this case, moving the piece and then removing the advanced pawn, if the intention was to remove the pawn, then yes, illegal move. If the pawn gets knocked over accidentally, then no.

The Niemann tactic the other day was a good example of how intermezzo checks lose the ability to capture en passent. Normally the threats created by moving the pawn can be dealt with by some capturing with checks, followed by dealing with the pawn threat (in that case, a pin). But the en passent opportunity has to be taken immediately, or it is lost. It feels slightly wrong that you can't do other stuff first, and then come back to dealing with the pawn. It almost feels like the whole en passent set-up has the feel of a check, in the urgency needed to deal with it.

(How do sensory boards handle this, and is there a correct sequence of piece touching and moving to follow? Do you pick up the piece you are capturing first, or do you move the piece you are capturing with first, place it on the square behind the pawn you are capturing, and then remove the pawn you have captured? A sensory board would record the move Bg6 and then squawk that a pawn had been knocked off the board and needs to be replaced on g5.)

[Alex McFarlane]

Do you think that deliberate removal of a piece from the board, other than as a result of a legal capture, could usefully be added to the actions "treated and punished as an illegal move"

Definitely not as this definition would cause promotion to be classified as an illegal move!!

[Chris Goodall]

Do you think that deliberate removal of a piece from the board, other than as a result of a legal capture, could usefully be added to the actions "treated and punished as an illegal move"

Definitely not as this definition would cause promotion to be classified as an illegal move!!

Okay, yes, in the Platonic realm the piece remains on the board and is promoted to a new rank, but in practice a piece of wood is removed from the board and a different piece added.

Proposed 7.5.4½
If a player, in the course of a move other than a pawn promotion, intentionally:
a) removes a piece from the board that has not been legally captured;
b) adds a piece to the board;
it shall be considered and penalized as if an illegal move.

You can obviously treat the addition of any object to the board as a distraction, but I feel like the advantage gained by playing Re1 with a rook that you've borrowed from the captured pieces on the board next to yours, is of a different nature than the advantage gained by adding a Cheesy Wotsit to e1, so deserves a stiffer punishment.