h#9.5
8/8/4p3/4k3/8/8/2q5/K3N3 w - - 0 1
- Nf3+ Kf4 Nd2 Qd1+ Kb2 e5 Kc3 e4 Kd4 Kg3 Ke5 Kf2 Kf4 Ke1 Kg3 e3 Kg2 e2 Nf3#
KNvkqp
5 pieces.
- h#11.5
- longest mate
- h#9.5
- deepest unique
- 194
- positions at that depth
- h#9.5
- deepest dual
- h#8
- deepest strict dual
- 480,993,308
- positions with a helpmate
- 1,447,326
- with a unique solution
- 355,074,048
- cells in the plane
- 254,269,930 bytes
- on disk
Deepest unique problems
h#9.5
8/8/6p1/8/8/q1N5/8/K1k5 w - - 0 1
- Na2+ Kd2 Kb1 g5 Nc3 Qc1+ Ka2 g4 Kb3 g3 Kc4 g2 Kd4 g1=R Ne4+ Kd1 Kd3 Re1 Nf2#
pure model ideal promotion underpromotion switchback self-block nocapture
Note: the side to move is in check in the diagram.
h#9.5
8/8/5p2/5k2/1q6/8/8/K5N1 w - - 0 1
- Ne2 Qe1+ Kb2 Kg4 Kc2 f5 Kd3 f4 Ke4 Kh3 Kf5 Kg2 Kg4 Kf1 Kh3 f3 Kh2 f2 Ng3#
Deepest dual problems
Deepest dual with different first and last moves: h#8. The deepest dual overall is h#9.5, where the two solutions share a first or a last move.
h#8
8/7N/5k2/8/2p5/8/5q2/K7 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Kg6 Nf6 c3 Ne8 c2 Kb2 Kh5 Kc3 c1=R+ Kd3 Rc6 Ke4 Qh4+ Kf5 Rh6 Ng7#
- Kf7 Nf6 c3 Nd5 c2 Kb2 Ke8 Kc3 Qf8 Kd4 c1=R Ke5 Rc8 Ke6 Rd8 Nc7#
pure model ideal promotion underpromotion self-block nocapture umnov
Note: the side to move is in check in the diagram.
h#8
7N/8/7k/4p3/8/8/7q/K7 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Qh1+ Kb2 e4 Kc3 e3 Kd4 e2 Ke5 e1=R+ Kf6 Re7 Ng6 Rh7 Ne7 Qh5 Ng8#
- e4 Ng6 Qc7 Kb2 Qh7 Kc3 e3 Kd4 e2 Ke5 e1=R+ Kf6 Rh1 Ne5 Rh5 Ng4#
pure model ideal promotion underpromotion self-block nocapture umnov
h#8
8/3N4/6p1/8/1k6/q7/2K5/8 b - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
- Qa5 Kd3 Qh5 Ke4 Kc3 Ne5 Kd2 Kd5 Ke3 Ke6 Kf4 Kf7 Kg5 Kg8 Kh6 Nf7#
- g5 Nc5 g4 Nb3 g3 Kd3 g2 Kd4 g1=R Nc5 Rg5 Nd7 Ka4 Kc4 Ra5 Nb6#
pure model ideal promotion underpromotion switchback closed-walk self-block nocapture nocheck