h#6
8/8/7k/6Q1/4p3/8/8/K2n4 b - - 0 1
- Kh7 Kb1 e3 Kc2 e2 Kd3 e1=B Ke4 Bc3 Kf5 Bh8 Qg6#
pure model promotion underpromotion self-block nocapture nocheck
Note: the side to move is in check in the diagram.
KQvknp
5 pieces.
- h#7
- longest mate
- h#6
- deepest unique
- 18
- positions at that depth
- h#6
- deepest dual
- h#5
- deepest strict dual
- 476,409,256
- positions with a helpmate
- 23,800,539
- with a unique solution
- 355,074,048
- cells in the plane
- 232,110,017 bytes
- on disk
Deepest unique problems
h#6
8/6k1/5Q2/8/2p5/8/8/K2n4 b - - 0 1
- Kg8 Ka2 c3 Kb3 c2 Kc4 c1=Q+ Kd5 Qh6 Ke6 Qh8 Qf7#
pure model promotion self-block nocapture
Note: the side to move is in check in the diagram.
h#6
K7/1p6/2n5/8/8/8/4Q3/5k2 b - - 0 1
- Kg1 Kxb7 Kh1 Kxc6 Kg1 Kd5 Kh1 Ke4 Kg1 Kf3 Kh1 Qg2#
pure model ideal switchback single-piece single-piece:black nocheck
Note: the side to move is in check in the diagram.
Deepest dual problems
Deepest dual with different first and last moves: h#5. The deepest dual overall is h#6, where the two solutions share a first or a last move.
h#5
8/8/8/7k/8/6Q1/p7/K1n5 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Ne2 Qe5+ Kg4 Kb2 Kf3 Kc2 Kf2 Kd3 Ke1 Qxe2#
- Nb3+ Qxb3 Kg4 Qxa2 Kf3 Kb2 Ke2 Kc3+ Kd1 Qd2#
h#5
4k3/8/3Q4/8/8/np6/8/K7 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Nb1 Qf8+ Kd7 Kxb1 Kc6 Kb2 Kb5 Kc3 Ka4 Qb4#
- Nb5 Qe5+ Kd7 Kb2 Kc6 Kxb3 Kb6 Kc4 Ka5 Qxb5#