Helpmate tablebases Every solution to every position, precomputed.

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KQPvkn

5 pieces.

h#9
longest mate
h#8
deepest unique
7
positions at that depth
h#8
deepest dual
h#5
deepest strict dual
481,555,609
positions with a helpmate
29,042,579
with a unique solution
355,074,048
cells in the plane
300,759,852 bytes
on disk

Deepest unique problems

h#8

1K6/8/8/8/2n5/2P5/7Q/7k b - - 0 1

  1. Kxh2 Ka8 Nd6 c4 Kg3 c5 Kf4 cxd6 Ke5 d7 Kd6 Ka7 Kc7 Ka6 Kb8 d8=Q#

pure model ideal mirror promotion 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#5. The deepest dual overall is h#8, where the two solutions share a first or a last move.

h#5

8/8/8/7k/5n2/6Q1/1P6/K7 b - - 0 1

Two solutions, with different first and last moves (2 starts, 2 ends).

  1. Ne2 Qe5+ Kg4 Kb1 Kf3 Kc2 Kf2 Kd3 Ke1 Qxe2#
  2. Ng2 Qh2+ Kg4 Kb1 Kf3 Kc2 Kf2 Kd3 Ke1 Qg1#

pure model mirror

h#5

8/8/7k/8/8/8/2P5/Kn4Q1 b - - 0 1

Two solutions, with different first and last moves (2 starts, 2 ends).

  1. Kh5 Qxb1 Kg4 Kb2 Kf3 Kc3 Ke2 Qb5+ Kd1 Qf1#
  2. Kh7 Qa7+ Kg8 c4 Kf8 c5 Ke8 c6 Kd8 Qd7#

pure model ideal single-piece single-piece:black