# Forced mate

Acolyte
Posers and Puzzles 21 Apr '05 23:46
1. Acolyte
21 Apr '05 23:46
The usual definition of a forced mate is one in which no matter what one player does, the other can ensure checkmate by optimal play.

But can you think of a position in which no matter what the players do, checkmate within a certain number of moves is completely unavoidable? A more difficult challenge is to think of a position with such a forced mate, but one in which the mate may take several moves to occur. How many moves away from the inevitable mate can you manage?
2. 22 Apr '05 00:17
Originally posted by Acolyte
The usual definition of a forced mate is one in which no matter what one player does, the other can ensure checkmate by optimal play.

But can you think of a position in which no matter what the players do, checkmate within a certain number of moves is completely unavoidable? A more difficult challenge is to think of a position with such a forced mate, bu ...[text shortened]... e may take several moves to occur. How many moves away from the inevitable mate can you manage?

OK this is my best effort.

White has 2 black bishops as he has "queened" one of his pawns into a bishop (bishoped?) I think the position is legal.

With white to move, it's inevtiable that he can only move his pawn, which will reach the 8th rank in 6 moves, before the black king can take it. No other pieces can move.

Of course, this only works providing white doesn't turn his pawn into another bishop or a knight!!! ðŸ™‚
3. 22 Apr '05 01:03

I believe this is a good one. It's white to move and mate in 6, and I think it is unavoidable no matter what.
4. Palynka
Upward Spiral
22 Apr '05 01:53
Nice one! I think you can actually push both pawns one square back and make it 7, right?
5. BigDoggProblem
Just...the Dogg
22 Apr '05 01:55
Originally posted by Acolyte
The usual definition of a forced mate is one in which no matter what one player does, the other can ensure checkmate by optimal play.

But can you think of a position in which no matter what the players do, checkmate within a certain number of moves is completely unavoidable? A more difficult challenge is to think of a position with such a forced mate, bu ...[text shortened]... e may take several moves to occur. How many moves away from the inevitable mate can you manage?
My best effort is here:

...although it involves lots of promoted force!

Noam Elkies has done a mate in 10 (!):

http://www.xs4all.nl/~timkr/chess2/diary.htm

Item 267.
6. BigDoggProblem
Just...the Dogg
22 Apr '05 01:56
Originally posted by Palynka
Nice one! I think you can actually push both pawns one square back and make it 7, right?
No, because 1.d4 b6 would lead to stalemate.
7. 22 Apr '05 01:571 edit
Uhh. i guess. But they could both take a two stepper on the first one and I don't know if it counts when the PLAYER makes the CHOICE to drag it out, as I thought it was inevitable mates. So whatever.

EDIT: never mind. Above poster is correct