h#6
7N/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.
KQNvk
4 pieces.
- h#7
- longest mate
- h#6
- deepest unique
- 3
- positions at that depth
- h#5
- deepest dual
- h#3
- deepest strict dual
- 2,706,576
- positions with a helpmate
- 307,651
- with a unique solution
- 1,892,352
- cells in the plane
- 2,572,051 bytes
- on disk
Deepest unique problems
Only 2 distinct ideas exist at this depth.
h#6
8/7N/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.
h#3
5N2/8/8/8/Q7/8/8/K3k3 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kd2 Ka2 Kc1 Ka3 Kb1 Qd1#
- Ke2 Ne6 Kd2 Nd4 Kc1 Qc2#
set-play pure mirror single-piece single-piece:black nocapture nocheck
h#3
1N6/8/8/8/2Q5/8/8/K5k1 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kf2 Kb2 Ke1 Kc3 Kd1 Qf1#
- Kg2 Nc6 Kf2 Nd4 Ke1 Qe2#
set-play pure model mirror single-piece single-piece:black nocapture nocheck
h#3
8/6N1/8/8/8/8/2k5/K5Q1 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kb3 Kb1 Ka3 Kc2 Ka2 Qa7#
- Kd3 Kb2 Ke4 Kc3 Ke5 Qd4#
pure model ideal mirror single-piece single-piece:black nocapture nocheck