h#3
8/8/8/8/3R4/2k5/1R6/K3R3 b - - 0 1
- Kxd4 Rbb1 Kd3 Kb2 Kd2 Rbd1#
single-piece single-piece:black nocheck
Note: the solution begins with a capture.
KRRRvk
5 pieces.
- h#5
- longest mate
- h#3
- deepest unique
- 217
- positions at that depth
- h#3
- deepest dual
- h#2
- deepest strict dual
- 25,001,583
- positions with a helpmate
- 4,144,864
- with a unique solution
- 121,110,528
- cells in the plane
- 14,807,411 bytes
- on disk
Deepest unique problems
h#3
8/8/8/8/8/4R3/3RkR2/K7 b - - 0 1
- Kxe3 Kb2 Ke4 Kc3 Ke3 Rde2#
switchback single-piece single-piece:black kniest nocheck
Note: the diagram has no legal last move, so it cannot arise in a game.
h#3
8/8/8/8/8/4R3/4R3/1K1Rk3 b - - 0 1
- Kxd1 Ka2 Kc1 Kb3 Kb1 Re1#
pure mirror single-piece single-piece:black nocheck
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
8/8/8/8/7R/8/8/K2RRk2 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kf2 Rf1+ Ke2 Re4#
- Kg2 Rg4+ Kh2 Rh1#
single-piece single-piece:black nocapture umnov
Note: the side to move is in check in the diagram.
h#2
8/8/8/R7/7R/8/8/K3R1k1 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kf2 Ra2+ Kxe1 Rh1#
- Kg2 Rg4+ Kh2 Rh5#
pure model mirror single-piece single-piece:black kniest
Note: the side to move is in check in the diagram.
h#2
8/8/8/8/4R3/2R5/2k5/K2R4 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxd1 Rd3+ Kc1 Rc4#
- Kxc3 Kb1 Kb3 Rd3#
pure model ideal mirror single-piece single-piece:black
Note: the side to move is in check in the diagram; the solution begins with a capture.