h#7
8/8/8/8/8/5N2/1r3R2/K4k2 b - - 0 1
- Rxf2 Kb1 Ke2 Kb2 Kd3+ Kc1 Kc3 Kd1 Kb2 Nd4 Ka1 Kc1 Ra2 Nb3#
pure model ideal switchback self-block
Note: the side to move is in check in the diagram; the solution begins with a capture.
KRNvkr
5 pieces.
- h#10
- longest mate
- h#7
- deepest unique
- 9
- positions at that depth
- h#7
- deepest dual
- h#4
- deepest strict dual
- 156,434,997
- positions with a helpmate
- 13,054,468
- with a unique solution
- 121,110,528
- cells in the plane
- 98,273,988 bytes
- on disk
Deepest unique problems
h#7
8/8/kRN5/8/8/1r6/8/2K5 b - - 0 1
- Rxb6 Kc2 Kb5 Kb2 Kc4+ Ka3 Kc3 Ka4 Kb2 Nd4 Ka1 Ka3 Rb1 Nc2#
pure model ideal switchback self-block
Note: the side to move is in check in the diagram; the solution begins with a capture.
h#7
8/8/8/8/8/5N2/6r1/K4Rk1 b - - 0 1
- Kxf1 Kb1 Ke2 Kb2 Kd3+ Kc1 Kc3 Kd1 Kb2 Nd4 Ka1 Kc1 Ra2 Nb3#
pure model ideal switchback self-block
Note: the diagram has no legal last move, so it cannot arise in a game.
Deepest dual problems
Deepest dual with different first and last moves: h#4. The deepest dual overall is h#7, where the two solutions share a first or a last move.
h#4
8/N7/1r6/8/8/8/8/KR5k b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kg2 Nb5 Rh6 Nc3 Rh2 Nd1 Kh1 Ne3#
- Kh2 Nb5 Rg6 Nd4 Rg1 Nf3+ Kh1 Rxg1#
pure model switchback self-block single-piece single-piece:white
Note: the side to move is in check in the diagram.
h#4
1N6/4r3/8/8/8/4k3/3R4/K7 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Rc7 Rd8 Rc2 Nd7 Kd2 Nc5+ Kc1 Nb3#
- Rd7 Rb2 Rd2 Nc6 Ke2 Nd4+ Kd1 Rb1#
h#4
8/6N1/8/2r5/4k3/8/8/K1R5 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Rg5 Ne6 Kf5 Rc7 Kg6 Nf8+ Kh6 Rh7#
- Rh5 Ne6 Kf5 Nf8 Kg5 Rg1+ Kh6 Rg6#