The player of the White pieces was far too sporting to do such a thing, even assuming it crossed his mind. Even if he had done, I'm not sure that the Black player would have bothered continuing just on the off-chance that White would have missed it.
Still, just suppose, Black might have thought. Suppose he did miss it? After all, why would he seal if he'd seen the mate? As it happens a lot of players nearly did miss it, so he might very well have done. The player certainly considered other moves - ipso facto, he might not have played the right one.
Put yourself in Black's situation. You'd have to know, wouldn't you? I gots to know, as the gentleman on the right observed, and rightly so. You couldn't resign first and then see. You'd have to find out for real.
So I don't imagine it's impossible that the situation might actually occur of a mate on the move being available, a move being sealed nevertheless and a second session being arranged. And having clarified that, we can proceed to discuss an even more tenuous point, raised by Andrew in the comments:
Point of interest- if the person ...had sealed his mate, would he (I assume that the non-sealer keeps the envelope) actually need to turn up at the resumption?
As it happens, I know the answer. An unambiguous answer. Sort of unambiguous, anyway: because after looking it up I wondered whether what the law said - on principle - depended on circumstances that might not actually occur in practice.
When I went to look it up, I initially assumed that the answer would be implict, i.e. one would have to interpret the rule about checkmate ending the game, and apply it to this particular instance. Checkmate ends the game when delivered on the board, even if the flag falls before the clock is subsequently hit: so, in this instance, once the move was sealed it would be deemed to have been played at chckmate having occurred, even if the player who sealed failed (accidentally or deliberately) to arrive at the board.
One would then have to seek clarification, since one could argue that the move had not, in fact, been "played", that a sealed move is not a move as such until the player actually plays it: and we would have to refer it to Geurt Gijssen for a judgement from Olympus. (This is something I have in fact done before - see page five - following an odd incident in a Streatham and Brixton match.)
No need: it's there in black and white in the FIDE Laws of Chess, as long as you're clever and look at the Appendices. The relevant clause reads as follows:
A10. The player shall lose the game if he arrives at the chessboard more than one hour late for the resumption of an adjourned game (unless the rules of the competition or the arbiter decides otherwise).I did wonder, by the way, how it was that this particular circumstance has come to be covered by the rules. Did this actually happen in a game, which led to a controversy which meant the lawmakers had to pay it particular attention? Or was it just the product of idle speculation, such as caused this particular posting to be written? It might very easily have occurred in a real game: and somebody could seal a move and not actually realise it was mate, rather than having deliberately sealed mate to annoy the opponent. An honest error, rather than anything malign.
However, if the player who made the sealed move is the late player, the game is decided otherwise, if:
the absent player has won the game by virtue of the fact that the sealed move is checkmate.
Whatever the reason for the ruling, the ruling itself seems clear enough. A player who sealed such a move and then failed to turn up would still win. Or would they? I'm not entirely convinced. I think the FIDE Rules, on this and other matters, assume that an arbiter exists, is present and can - in relation to the sealed move - play it on the board at the time the playing session is due to start. That's the point - the arbiter has played the move on the board, it therefore exists and it's checkmate. The game is over.
But in league chess, no such person normally exists. There is no arbiter to play the move and it does not, therefore, necessarily appear on the board. If that is the principle of which this clause is based, that checkmate, once played on the board, ends the game - what happens if it has not been made on the board?
It's not a stupid point, because I can think of an obvious complication. Suppose the players were to agree to a draw before the resumption? The player who has sealed is not aware that mate has been delivered - perhaps neither of the players realises that mate is possible. Does it count as a draw? If the move is viewed as having been played once written on the scoresheet, surely the game is over already? So what happens then? Would that draw be invalid because a sealed move is viewed the same as any other move?
I don't know, I'm as confused as ever. Anyone for a quickplay finish?