Mate in 3 (BDP original)

Black has toyed with his opponent, but will soon regret the casual assurance with which he has handled the game.


White mates in 3

Inspired by Thread 49256.

Can this task (mate in 2 or more, vs. the maximum possible Black force) be done with only one White pawn?

Originally posted by BigDoggProblem
Black has toyed with his opponent, but will soon regret the casual assurance with which he has handled the game.

[fen]k2n4/6bq/1KPP4/1b2r2q/4n3/4rqq1/4q1qq/5q1q[/fen]
White mates in 3

Inspired by Thread 49256.

Can this task (mate in 2 or more, vs. the maximum possible Black force) be done with only [b]one White pawn?[/b]

It doesn't look to me you need the d pawn, the c pawn does the trick. Just push and the threat of either pxKn or p-c8 Q+ pretty much decides the tissue.

Originally posted by sonhouse
It doesn't look to me you need the d pawn, the c pawn does the trick. Just push and the threat of either pxKn or p-c8 Q+ pretty much decides the tissue.

Without the d pawn 1. c7 is met by any check (such as Qh6+) and black has mate not white.

EDIT: Moving the e5 rook anywhere also gives black mate rather than white.

Originally posted by XanthosNZ
Without the d pawn 1. c7 is met by any check (such as Qh6+) and black has mate not white.

EDIT: Moving the e5 rook anywhere also gives black mate rather than white.

Good point. Guess thats why I am 1600 and you 2100!

Originally posted by sonhouse
It doesn't look to me you need the d pawn, the c pawn does the trick. Just push and the threat of either pxKn or p-c8 Q+ pretty much decides the tissue.

I tried very hard to make a position where a single white pawn forces mate (in more than just one move; it's much harder when Black is allowed a move to defend himself!), but to no avail.

I invite others to break my record, if they dare. I've shown a #3 with only two White pawns, so the only way to best that is to use a single White pawn(!)

Conditions:
- White must force mate in 2 or more moves (NO mates in 1 - too easy!)
- Black has maximal force (9Q, 2R, 2B, 2N)
- The position must be legal
- I would prefer that the key (first) move NOT be 1.KxQ or PxQ

Originally posted by BigDoggProblem
I tried very hard to make a position where a single white pawn forces mate (in more than just one move; it's much harder when Black is allowed a move to defend himself!), but to no avail.

I invite others to break my record, if they dare. I've shown a #3 with only two White pawns, so the only way to best that is to use a single White pawn(!)

Cond ...[text shortened]...
- The position must be legal
- I would prefer that the key (first) move NOT be 1.KxQ or PxQ

Contrived but legal and satisfying all criteria.

Originally posted by XanthosNZ
Contrived but legal and satisfying all criteria.

[fen]rqqqbk2/nqqqb2K/n1qqqrP1/8/8/8/8/8 w - - 0 1[/fen]

What if he gets a rook instead?🙂

Originally posted by sonhouse
What if he gets a rook instead?🙂

Then it's not mate. 😕

Originally posted by XanthosNZ
Contrived but legal and satisfying all criteria.

[fen]rqqqbk2/nqqqb2K/n1qqqrP1/8/8/8/8/8 w - - 0 1[/fen]

Ah, of course...I didn't consider a checking key, which makes the whole task trivial (trivial, because the Queens/Ra8/Knights can be placed on many different squares, and the mate still works). Well done!

I'd suggest doing one without the checking key, like my #3 problem, but the key in my problem isn't very good either. 1.c7 is a really obvious first move. With only a White King and Pawn on the board, the odds of getting a good key are slim.

Originally posted by BigDoggProblem
Ah, of course...I didn't consider a checking key, which makes the whole task trivial (trivial, because the Queens/Ra8/Knights can be placed on many different squares, and the mate still works). Well done!

I'd suggest doing one without the checking key, like my #3 problem, but the key in my problem isn't very good either. 1.c7 is a really obv ...[text shortened]... move. With only a White King and Pawn on the board, the odds of getting a good key are slim.

The only good key would be a king move and I can't even begin to think how to construct a position where that would work as for one the first move can therefore not be a check (and then you have to ensure black has no checks that force mate) and then you need to then force mate in response to all black replies (including king moves).

Originally posted by XanthosNZ
The only good key would be a king move and I can't even begin to think how to construct a position where that would work as for one the first move can therefore not be a check (and then you have to ensure black has no checks that force mate) and then you need to then force mate in response to all black replies (including king moves).

The wK is usually needed to help in the mate, but a flight-taking key isn't any better than a key like 1.c7. Also, the wK seems too exposed for two quiet moves in a row (1.K~ followed by 2.c7, or some such). Almost any black check is lethal, and it's hard enough to keep White out of check for just one move, let alone two.