h#3
8/8/8/8/3Q4/3k4/2R5/K1Q5 b - - 0 1
- Kxd4 Kb2 Ke4 Qf4+ Kd3 Rd2#
closed-walk single-piece single-piece:black
Note: the side to move is in check in the diagram; the solution begins with a capture.
KQQRvk
5 pieces.
- h#4
- longest mate
- h#3
- deepest unique
- 775
- positions at that depth
- h#3
- deepest dual
- h#2
- deepest strict dual
- 66,347,813
- positions with a helpmate
- 11,984,404
- with a unique solution
- 121,110,528
- cells in the plane
- 57,496,154 bytes
- on disk
Deepest unique problems
h#3
8/8/8/8/8/4Q3/1RQk4/K7 b - - 0 1
- Kxe3 Ka2 Kd4 Qe4+ Kc3 Rc2#
single-piece single-piece:black
Note: the diagram has no legal last move, so it cannot arise in a game.
h#3
8/3Q4/8/8/8/4Q3/3k2R1/K7 b - - 0 1
- Kxe3 Qf5 Kd4 Kb2 Kc4 Rg4#
pure model ideal mirror 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 775 positions at this depth.
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
8/8/8/8/6R1/3Q4/3k4/K3Q3 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxe1 Qe3+ Kf1 Rg1#
- Kxd3 Rg3+ Kc2 Rc3#
single-piece single-piece:white single-piece:black
Note: the diagram has no legal last move, so it cannot arise in a game.
h#2
8/8/8/8/7R/4Q3/4k3/1K3Q2 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxf1 Qf3+ Kg1 Rh1#
- Kxe3 Rh3+ Kd2 Rd3#
single-piece single-piece:white single-piece:black
Note: the diagram has no legal last move, so it cannot arise in a game.
h#2
8/8/8/R7/1Q6/2kQ4/8/1K6 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxd3 Qf4 Kc3 Ra3#
- Kxb4 Rb5+ Ka4 Qb3#
pure model ideal mirror switchback single-piece single-piece:black
Note: the diagram has no legal last move, so it cannot arise in a game.