Helpmate tablebases Every solution to every position, precomputed.

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KRvkqr

5 pieces.

h#8
longest mate: h#6.5
deepest unique: 5
positions at that depth: h#6.5
deepest dual: h#6
deepest strict dual: 133,724,759
positions with a helpmate: 4,004,956
with a unique solution: 121,110,528
cells in the plane: 71,970,508 bytes
on disk

Deepest unique problems

h#6.5

8/8/5k2/8/6R1/8/2q4r/1K6 w - - 0 1

Ka1 Qb1+ Kxb1 Rh6 Kc2 Rg6 Kd3 Kg7 Ke4 Kh6 Kf5 Rg7 Rh4#

pure model ideal switchback self-block umnov

Note: the side to move is in check in the diagram.

h#6.5

5k2/8/8/8/3R4/8/2qr4/1K6 w - - 0 1

Ka1 Qb1+ Kxb1 Rd1+ Kc2 Rg1 Kd3 Kg7 Ke4 Kh6 Kf5 Rg7 Rh4#

pure model ideal switchback self-block umnov

Note: the side to move is in check in the diagram.

h#6.5

8/5k2/8/8/6R1/8/2qr4/1K6 w - - 0 1

Ka1 Qb1+ Kxb1 Rd6 Kc2 Rg6 Kd3 Kg7 Ke4 Kh6 Kf5 Rg7 Rh4#

pure model ideal switchback self-block umnov

Note: the side to move is in check in the diagram.

Deepest dual problems

Deepest dual with different first and last moves: h#6. The deepest dual overall is h#6.5, where the two solutions share a first or a last move.

Only one position exists at this depth.

h#6

7k/8/8/8/6q1/8/3r3R/K7 b - - 0 1

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

Kg7 Kb1 Rd6 Kc2 Rg6 Kd3 Qh3+ Ke4 Kh6 Kf4 Kh5 Rxh3#
Qh5 Kb1 Rd7 Kc2 Rg7 Kd3 Kh7 Ke4 Qh4+ Kf5 Kh6 Rxh4#

pure model ideal self-block

Note: the side to move is in check in the diagram.