18 Dec 06
Originally posted by David113Only corner mates are possible. a8 is out because wK>a6 and N>c7 is already 7 moves, and the wN must come from a6, which is where wK needs to be. h8/h1 are too far, even with 8 moves. That means bK has to get mated on a1.
Reminds me of this problem:
[fen]1Nk5/8/1r6/8/8/8/8/K7 b - - 0 1[/fen]
Helpmate in 8 moves.
7 of Black's moves are King moves, so only one move is left for ...Rb1. wK must be on a3 and wN on c2 to mate. wK can only go to a3 after bK goes to a1, so Black must keep the move Rb1 in reserve until the end, so he has something to do while waiting for the deathblow.
The problem is that wK cannot just go straight up the a-file and back, because he reaches a3 in an even number of moves, while his N reaches c2 in an odd number of moves. The stipulation demands an even parity, so White needs to lose a tempo with his King at some point.
1.Kb7! Nc6 2.Ka6 Ka2 3.Kb5 Kb2 4.Kc4+ Ka3 5.Kc3 Ka4 6.Kb2 Nd4 This is the reason for the first two moves. A wN on b4 blocks ...Rb6-b1. 7.Ka1 Ka3 8.Rb1 Nc2#
19 Dec 06
Originally posted by BigDoggProblemWell done.
Only corner mates are possible. a8 is out because wK>a6 and N>c7 is already 7 moves, and the wN must come from a6, which is where wK needs to be. h8/h1 are too far, even with 8 moves. That means bK has to get mated on a1.
7 of Black's moves are King moves, so only one move is left for ...Rb1. wK must be on a3 and wN on c2 to mate. wK can only go to ...[text shortened]... is the reason for the first two moves. A wN on b4 blocks ...Rb6-b1. [b]7.Ka1 Ka3 8.Rb1 Nc2#[/b]
20 Dec 06
Originally posted by BigDoggProblemI think I saw this puzzle once. I think the key move was 1. Qe1. But I cant remember after that without looking it up.
Thanks for the link. The last problem on the page is brilliant.
N. Hoeg, Skakbladet 1907
[fen]8/8/6p1/5pP1/5P1K/5PpP/4p2p/2Q2Bkr w - - 0 1[/fen]
White to play and end the game in two moves.
20 Dec 06
Originally posted by hypotheticalIt's beautiful. 1.Qe1 and now
I think I saw this puzzle once. I think the key move was 1. Qe1. But I cant remember after that without looking it up.
1 .... exf1=Q 2.Kxg3 forcing Qxe1#
1. ... exf1=R 2.Qxg3#
1. ... exf1=B 2.Kxg3 stalemate
1. ... exf1=N 2.Qxf2 and now both gxf2 and Kxf2 stalemate
1. ... g2 2.Bxe2#
The beauty is that in these few variations, black both black and white gets mated or stalemated.