h#8.5
6k1/8/8/1p6/8/8/1r6/K6N w - - 0 1
- Ng3 Rh2 Kb1 Rh8 Kc2 b4 Kd3 b3 Ke4 b2 Kf5 b1=R Kg6 Rb8 Nf5 Rf8 Ne7#
pure model ideal promotion underpromotion self-block nocapture nocheck
KNvkrp
5 pieces.
- h#11.5
- longest mate
- h#8.5
- deepest unique
- 46
- positions at that depth
- h#8.5
- deepest dual
- h#8
- deepest strict dual
- 520,342,046
- positions with a helpmate
- 3,516,273
- with a unique solution
- 355,074,048
- cells in the plane
- 206,833,802 bytes
- on disk
Deepest unique problems
h#8.5
7k/8/8/4p3/8/1r6/3N4/K7 w - - 0 1
- Ka2 Rh3 Nf3 e4 Kb3 e3 Kc4 e2 Kd5 e1=B Ke6 Bc3 Kf7 Bg7 Ne5 Rh7 Ng6#
h#8.5
8/8/3p4/8/8/1k6/N7/rK6 w - - 0 1
- Kxa1 d5 Kb1 d4 Kc1 d3 Kd2 Kb2 Nb4 Ka1 Kc3 d2 Kb3 d1=R Ka3 Rb1 Nc2#
pure model ideal promotion underpromotion switchback self-block kniest phoenix nocheck umnov
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#8. The deepest dual overall is h#8.5, where the two solutions share a first or a last move.
Only one position exists at this depth.
h#8
5N2/6k1/2p5/8/8/8/1r6/K7 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Rb1+ Ka2 Kf6 Ka3 Ke5 Ka4 Kd4 Ne6+ Kc3 Nd4 Kb2 Kb4 Ka1+ Ka3 c5 Nc2#
- Ra2+ Kb1 Kf6 Kc1 Ke5 Kd1 Kd4 Ne6+ Kc3 Nd4 Kb2 Kd2 Ka1+ Kc1 c5 Nb3#