Helpmate tablebases Every solution to every position, precomputed.

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KNvkqb

5 pieces.

h#11.5
longest mate
h#9.5
deepest unique
1
positions at that depth
h#9.5
deepest dual
h#7.5
deepest strict dual
152,403,841
positions with a helpmate
382,525
with a unique solution
121,110,528
cells in the plane
56,469,554 bytes
on disk

Deepest unique problems

Only one position exists at this depth.

h#9.5

7k/6N1/8/8/8/8/b2q4/1K6 w - - 0 1

  1. Ka1 Kg8 Nf5 Kf7 Ne3 Ke6 Nc2 Kd5 Kb2 Kc4 Ka3 Kc3 Ka4 Kb2 Nd4 Ka1 Ka3 Bb1 Nb3#

pure model switchback self-block nocapture nocheck

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

Published as Sheglow (1998)

  • Sheglow, Wiktor S. — Suomen Tehtäväniekat, No. (291), 05-06/1998

Deepest dual problems

Deepest dual with different first and last moves: h#7.5. The deepest dual overall is h#9.5, where the two solutions share a first or a last move.

Only 2 distinct ideas exist at this depth.

h#7.5

8/8/5k2/8/8/1b6/3q4/K3N3 w - - 0 1

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

  1. Kb1 Qc1+ Kxc1 Ke5 Kd2 Kd4 Ke2 Kc3 Ke3 Kb2 Kd2 Ka1 Kc1 Ba2 Nc2#
  2. Nf3 Ba2 Nxd2 Ke5 Kb2 Kd4 Ka3 Kc3 Ka4 Kb2 Kb4 Ka1 Ka3 Bb1 Nb3#

pure model ideal closed-walk self-block

h#7.5

8/8/5k2/8/8/1b6/4q3/K3N3 w - - 0 1

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

  1. Kb1 Ke5 Kc1 Qd2+ Kxd2 Kd4 Ke2 Kc3 Ke3 Kb2 Kd2 Ka1 Kc1 Ba2 Nc2#
  2. Nf3 Ba2 Nd2 Ke5 Kb2 Kd4 Ka3 Kc3 Ka4 Kb2 Kb4 Ka1 Ka3 Bb1 Nb3#

pure model ideal closed-walk self-block