A260954 Longest checkmates in chess with n pieces on board.

28, 43, 127, 262, 549

Offset

3,1

Comments

Results based on research on the Nalimov and Lomonosov Endgame Tablebases.

The results for 6 and 7 pieces ignore the 50-move rule.

FEN:

3 pieces, 28 moves: 8/8/8/1k6/8/8/K5P1/8 w - - 0 1

4 pieces, 43 moves: 8/5k2/2PK4/5r2/8/8/8/8 w - - 0 1

5 pieces, 127 moves: 8/8/8/8/1p2P3/4P3/1k6/3K4 w - - 0 1

6 pieces, 262 moves: 6k1/5n2/8/8/8/5n2/1RK5/1N6 w - - 0 1

7 pieces, 549 moves: 1n1k4/6Q1/5KP1/8/7b/1r6/8/8 w - - 0 1

Links

Table of n, a(n) for n=3..7.

Eiko Bleicher, Nalimov Endgame Tablebases

ChessOK, Lomonosov Endgame Tablebases

Kirill Kryukov, Longest checkmates in chess

Wikipedia, Fifty-move rule

Example

With 3 pieces on board (n=3) the longest checkmate requires 28 moves. That is with two kings and a pawn. The FEN strings above give the exact placement of the pieces.

Crossrefs

Sequence in context: A056031 A061826 A326234 * A349495 A169962 A219685

Adjacent sequences: A260951 A260952 A260953 * A260955 A260956 A260957

Keyword

nonn,more,hard,fini

Author

Panagiotis Tsikogiannopoulos, Sep 04 2015

Status

approved