h#6
7B/7k/8/6Q1/8/8/8/K7 b - - 0 1
- Kxh8 Kb2 Kh7 Kc3 Kh8 Kd4 Kh7 Ke5 Kh8 Kf6 Kh7 Qg7#
switchback single-piece single-piece:black pendulum nocheck
Note: the solution begins with a capture.
KQBvk
4 pieces.
- h#7
- longest mate
- h#6
- deepest unique
- 3
- positions at that depth
- h#5
- deepest dual
- h#3
- deepest strict dual
- 2,630,189
- positions with a helpmate
- 447,981
- with a unique solution
- 1,892,352
- cells in the plane
- 2,350,292 bytes
- on disk
Deepest unique problems
Only 2 distinct ideas exist at this depth.
h#6
8/7B/7k/6Q1/8/8/8/K7 b - - 0 1
- Kxh7 Kb2 Kh8 Kc3 Kh7 Kd4 Kh8 Ke5 Kh7 Kf6 Kh8 Qg7#
pure model ideal switchback 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#5, where the two solutions share a first or a last move.
Only one position exists at this depth.
h#3
8/8/8/8/3k4/2Q4B/8/K7 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Ke4 Qe1+ Kd3 Ka2 Kc2 Bf5#
- Kd5 Qa5+ Kc4 Kb1 Kb3 Be6#
mirror single-piece single-piece:black nocapture
Note: the side to move is in check in the diagram.