Helpmate tablebases Every solution to every position, precomputed.

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KRNvkq

5 pieces.

h#7
longest mate
h#5.5
deepest unique
2
positions at that depth
h#5.5
deepest dual
h#4.5
deepest strict dual
142,920,524
positions with a helpmate
8,535,976
with a unique solution
121,110,528
cells in the plane
99,409,414 bytes
on disk

Deepest unique problems

Only one distinct idea exists at this depth: 2 positions share a solution.

h#5.5

8/N7/8/7k/R7/8/8/Kq6 w - - 0 1

  1. Kxb1 Kg5 Ra6 Kf4 Nb5 Ke3 Re6+ Kd2 Re2+ Kd1 Nc3#

single-piece single-piece:black

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#4.5. The deepest dual overall is h#5.5, where the two solutions share a first or a last move.

h#4.5

8/8/8/N7/5k2/q6R/8/K7 w - - 0 1

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

  1. Kb1 Qg3 Nb3 Ke3 Nc1 Kd2 Kb2 Qe1 Rd3#
  2. Rxa3 Ke4 Ra4+ Kd3 Rd4+ Kc2 Rd2+ Kc1 Nb3#

self-block single-piece single-piece:black

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

h#4.5

8/8/8/6k1/8/N7/8/Kq5R w - - 0 1

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

  1. Kxb1 Kf4 Nb5 Ke3 Re1+ Kd2 Re2+ Kd1 Nc3#
  2. Rxb1 Kf4 Rb2 Ke3 Nc2+ Kd2 Ne3+ Kc1 Rc2#

single-piece single-piece:black umnov

Note: the side to move is in check in the diagram; the solution begins with a capture.

h#4.5

8/8/8/6k1/8/8/q6R/K2N4 w - - 0 1

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

  1. Kxa2 Kf4 Nf2 Ke3 Kb3 Kd2 Ne4+ Kc1 Rh1#
  2. Rxa2 Kf4 Nc3 Ke3 Kb2 Kd2 Kb3+ Kc1 Rc2#

pure model ideal mirror single-piece single-piece:black

Note: the side to move is in check in the diagram; the solution begins with a capture.