h#7
7Q/7k/7B/8/8/8/2B5/K7 b - - 0 1
- Kxh8 Kb2 Kg8 Kc3 Kf7 Kd3 Kg6 Ke4 Kh5 Kf5 Kh4 Bg5+ Kh5 Bd1#
switchback single-piece single-piece:black
Note: the diagram has no legal last move, so it cannot arise in a game.
KQBBvk
5 pieces.
- h#8
- longest mate
- h#7
- deepest unique
- 1
- positions at that depth
- h#6
- deepest dual
- h#3
- deepest strict dual
- 75,197,106
- positions with a helpmate
- 12,536,596
- with a unique solution
- 121,110,528
- cells in the plane
- 66,555,344 bytes
- on disk
Deepest unique problems
Only one position exists at this depth.
Deepest dual problems
Deepest dual with different first and last moves: h#3. The deepest dual overall is h#6, where the two solutions share a first or a last move.
Only one position exists at this depth.
h#3
8/8/8/3B4/3k4/2Q5/8/K1B5 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kxc3 Ka2 Kb4 Bd2+ Ka4 Bc6#
- Kxd5 Qa5+ Kc4 Bd2 Kb3 Qa2#
pure model ideal mirror single-piece single-piece:black zilahi
Note: the side to move is in check in the diagram; the solution begins with a capture.