h#6
8/7k/6R1/8/8/8/P7/K7 b - - 0 1
- Kh8 a4 Kh7 a5 Kh8 a6 Kh7 a7 Kh8 a8=Q+ Kh7 Qg8#
promotion excelsior excelsior:white switchback single-piece single-piece:white single-piece:black pendulum nocapture
KRPvk
4 pieces.
- h#8
- longest mate
- h#6
- deepest unique
- 25
- positions at that depth
- h#7
- deepest dual
- h#5
- deepest strict dual
- 9,060,230
- positions with a helpmate
- 655,334
- with a unique solution
- 5,548,032
- cells in the plane
- 4,807,793 bytes
- on disk
Deepest unique problems
h#6
7k/8/6R1/8/8/8/5P2/K7 b - - 0 1
- Kh7 f4 Kh8 f5 Kh7 f6 Kh8 f7 Kh7 Rg7+ Kh8 f8=Q#
set-play promotion excelsior excelsior:white switchback single-piece single-piece:black pendulum nocapture
h#6
K7/8/8/8/8/8/1P3R2/6k1 b - - 0 1
- Kh1 b4 Kg1 b5 Kh1 b6 Kg1 b7 Kh1 b8=Q Kg1 Qh2#
set-play promotion excelsior excelsior:white switchback single-piece single-piece:white single-piece:black pendulum nocapture nocheck
Deepest dual problems
Deepest dual with different first and last moves: h#5. The deepest dual overall is h#7, where the two solutions share a first or a last move.
Only one position exists at this depth.
h#5
K7/8/8/8/1P6/8/5R2/5k2 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Ke1 b5 Kd1 b6 Kc1 b7 Kb1 b8=Q+ Ka1 Qb2#
- Kg1 b5 Kh1 b6 Kg1 b7 Kh1 b8=Q Kg1 Qh2#
pure model promotion switchback single-piece single-piece:white single-piece:black nocapture
Note: the side to move is in check in the diagram.