h#3
8/8/8/8/4Q3/B2k4/1Q6/K7 b - - 0 1
- Kxe4 Kb1 Ke3 Bc5+ Kd3 Qc2#
pure model ideal closed-walk single-piece single-piece:black
Note: the side to move is in check in the diagram; the solution begins with a capture.
KQQBvk
5 pieces.
- h#4
- longest mate
- h#3
- deepest unique
- 293
- positions at that depth
- h#3
- deepest dual
- h#2
- deepest strict dual
- 68,642,516
- positions with a helpmate
- 13,917,473
- with a unique solution
- 121,110,528
- cells in the plane
- 63,695,456 bytes
- on disk
Deepest unique problems
h#3
8/8/8/8/3Q4/1Bk5/2Q5/K7 b - - 0 1
- Kxd4 Qg6 Kc5 Kb2 Kb4 Qb6#
pure model ideal single-piece single-piece:black nocheck
Note: the diagram has no legal last move, so it cannot arise in a game.
h#3
8/8/8/8/4Q3/2Qk4/3B4/K7 b - - 0 1
- Kxe4 Qb4+ Kd3 Be1 Kc2 Qb1#
switchback single-piece single-piece:black
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#2. The deepest dual overall is h#3, where the two solutions share a first or a last move.
h#2
7Q/8/5B1Q/8/8/8/8/K1k5 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kd1 Qb8 Kc2 Qb1#
- Kc2 Bc3 Kd1 Qd2#
pure single-piece single-piece:white single-piece:black nocapture nocheck
Note: the side to move is in check in the diagram.
h#2
7B/8/8/8/8/8/2Q5/K2kQ3 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxe1 Bd4 Kf1 Qf2#
- Kxc2 Qe2+ Kc1 Bb2#
pure model ideal single-piece single-piece:black
Note: the diagram has no legal last move, so it cannot arise in a game.
h#2
8/8/8/8/8/8/5Q1B/K2Qk3 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxd1 Qe2+ Kc1 Bf4#
- Kxf2 Qd3 Ke1 Bg3#
pure model mirror switchback single-piece single-piece:black
Note: the diagram has no legal last move, so it cannot arise in a game.