h#2
5Q2/4Q3/8/8/8/8/8/K1Qk4 b - - 0 1
- Kxc1 Qf2 Kd1 Qee1#
switchback single-piece single-piece:black nocheck
Note: the side to move is in check in the diagram; the solution begins with a capture.
KQQQvk
5 pieces.
- h#3
- longest mate
- h#2
- deepest unique
- 3,150
- positions at that depth
- h#2
- deepest dual
- h#1.5
- deepest strict dual
- 20,913,947
- positions with a helpmate
- 4,170,311
- with a unique solution
- 121,110,528
- cells in the plane
- 21,320,991 bytes
- on disk
Deepest unique problems
h#2
2Q5/2Q5/8/8/8/8/8/K1kQ4 b - - 0 1
- Kxd1 Qh2 Ke1 Qc1#
mirror single-piece single-piece:black nocheck
Note: the diagram has no legal last move, so it cannot arise in a game.
h#2
8/Q7/8/Q7/8/8/8/K3kQ2 b - - 0 1
- Kxf1 Qa2 Ke1 Qg1#
mirror switchback single-piece single-piece:black nocheck
Note: the diagram has no legal last move, so it cannot arise in a game.
Chosen from the first 500 of 3,150 positions at this depth.
Deepest dual problems
Deepest dual with different first and last moves: h#1.5. The deepest dual overall is h#2, where the two solutions share a first or a last move.
h#1.5
Q7/8/6Q1/8/6Q1/8/8/K1k5 w - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Qgg2 Kd1 Qb1#
- Qd6 Kc2 Qc4#
h#1.5
8/Q3Q3/8/8/8/8/8/QK3k2 w - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Qh4 Kg2 Qaf2#
- Q7a2 Kg1 Qe1#
h#1.5
8/2Q1Q3/8/8/8/7k/8/QK6 w - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Qe1 Kg2 Qcg3#
- Qeg7 Kh4 Qh2#