09 Oct 07
1 edit
1... Kg4! 2. Kg1 (A) Kg3 3. Kh1 Nh4 4. f5 (B) Nf3 5. f6 Nd1/g4 6. f7 Nf2#
(A) 2. Kh1 Kg3 3. Kg1 Nh4 4. Kh1(C) Nf3 5. f5 Nd1/g4 6. f6 Nf2#
(B) 4. Kg1 Nf3+ 5. Kh1 Nd1/g4 6. f5 Nf2#
(C) 4. f5 Nf3+ 5. Kh1 Nd1/g4 6. f6 Nf2#
In words: After 1... Kg4! White's K gets trapped in the corner, gets stalemated and is forced to move his pawn while black proceeds to deliver mate.
09 Oct 07
Originally posted by magnublmThats correct, mate can be forced with 2 knights when the weaker side has a pawn behind a certain place. This is because with the pawn stalemate can be avoided but the mate is horrendously complex and if anyone succeeds in doing it here they are probably using a tablebase.
I didn't think mate could be *forced* with just two knights. I'm guessing the white pawn is part of the reason it's forced in this puzzle?
09 Oct 07
Originally posted by Dragon FireMate can be forced with only one knight with the aid of the opponents judas pawn.
Thats correct, mate can be forced with 2 knights when the weaker side has a pawn behind a certain place. This is because with the pawn stalemate can be avoided but the mate is horrendously complex and if anyone succeeds in doing it here they are probably using a tablebase.
09 Oct 07
Originally posted by Dragon FireI did most certainly not use a tablebase to arrive at the solution, just shuffling around some pieces. It's not that hard really.
Thats correct, mate can be forced with 2 knights when the weaker side has a pawn behind a certain place. This is because with the pawn stalemate can be avoided but the mate is horrendously complex and if anyone succeeds in doing it here they are probably using a tablebase.
09 Oct 07
Originally posted by Dragon FireI created these tablebases when I was in eleventh grade three decades ago. Geez, there are only a few dozen possibilities in this position.
Thats correct, mate can be forced with 2 knights when the weaker side has a pawn behind a certain place. This is because with the pawn stalemate can be avoided but the mate is horrendously complex and if anyone succeeds in doing it here they are probably using a tablebase.
These are old-style Ruy Lopez type tablebases--using a quill pen, I list every possible white response to black's choice moves.
After 1...Kg4, white has two legal moves. In both cases 2...Kg3 forces the other, etc.
11 Oct 07
1 edit
Originally posted by zzywThe position given here is not difficult but most K & 2N vs K & P would require a tablebase to solve and if achieved in a nornal game here would be highly suspect.
I did most certainly not use a tablebase to arrive at the solution, just shuffling around some pieces. It's not that hard really.
11 Oct 07
Originally posted by WulebgrSorry for confusion I did not mean this particular position which is indeed solvable but rather the sort of positions likely to occur in actual play which may have a forced mate is 40+ moves. It is these positions that I refer to as (probably) requiring a tablebase.
I created these tablebases when I was in eleventh grade three decades ago. Geez, there are only a few dozen possibilities in this position.
These are old-style Ruy Lopez type tablebases--using a quill pen, I list every possible white response to black's choice moves.
After 1...Kg4, white has two legal moves. In both cases 2...Kg3 forces the other, etc.
11 Oct 07
Originally posted by Dragon FireSorry I went after you as a rattlesnake, then.
Sorry for confusion I did not mean this particular position which is indeed solvable but rather the sort of positions likely to occur in actual play which may have a forced mate is 40+ moves. It is these positions that I refer to as (probably) requiring a tablebase.