h#4
N7/8/8/8/8/1Q6/7Q/K6k b - - 0 1
- Kxh2 Qg8 Kh3 Nc7 Kh4 Ne6 Kh5 Qg5#
pure model single-piece single-piece:black nocheck
Note: the side to move is in check in the diagram; the solution begins with a capture.
KQQNvk
5 pieces.
- h#5
- longest mate
- h#4
- deepest unique
- 18
- positions at that depth
- h#4
- deepest dual
- h#3
- deepest strict dual
- 70,274,406
- positions with a helpmate
- 13,718,058
- with a unique solution
- 121,110,528
- cells in the plane
- 62,035,780 bytes
- on disk
Deepest unique problems
h#4
kQ6/8/8/8/8/8/2Q5/1K5N b - - 0 1
- Kxb8 Qh7 Kc8 Ng3 Kd8 Nf5 Ke8 Qe7#
pure model single-piece single-piece:black nocheck
Note: the side to move is in check in the diagram; the solution begins with a capture.
h#4
6Qk/8/8/8/8/8/5Q2/NK6 b - - 0 1
- Kxg8 Qa7 Kf8 Nb3 Ke8 Nc5 Kd8 Qd7#
pure model single-piece single-piece:black nocheck
Note: the side to move is in check in the diagram; the solution begins with a capture.
Deepest dual problems
Deepest dual with different first and last moves: h#3. The deepest dual overall is h#4, where the two solutions share a first or a last move.
h#3
3N4/8/8/8/8/8/7Q/K4Qk1 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxf1 Kb2 Ke1 Kc3 Kd1 Qd2#
- Kxh2 Ne6 Kg3 Nf4 Kh2 Qg2#
switchback single-piece single-piece:black kniest nocheck zilahi
Note: the diagram has no legal last move, so it cannot arise in a game.
h#3
8/N7/8/8/7Q/5Qk1/8/1K6 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxf3 Nb5 Ke2 Qf2+ Kd1 Nc3#
- Kxh4 Nc6 Kg5 Ne5 Kh4 Qg4#
pure model mirror switchback single-piece single-piece:black kniest
Note: the diagram has no legal last move, so it cannot arise in a game.
h#3
8/8/N7/8/5Q2/6kQ/8/3K4 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxh3 Nc5 Kg2 Ne4 Kh3 Qg3#
- Kxf4 Nb4 Ke4 Qf5+ Ke3 Nc2#
pure model ideal mirror switchback single-piece single-piece:black kniest
Note: the diagram has no legal last move, so it cannot arise in a game.