This page contains the moves up to ply 11 that determine all the previous moves uniquely. If the move ends with a checkmate symbol (#), then the move also determines the game.
The prime example in this category is the problem "Construct a game of chess ending with the move 6. gxf8=N#" by Peter Rösler, Problemkiste, 8/1994, and appearing as the ChessBase puzzle of Christmas 2000.
By "move" I mean its representation in Standard Algebraic Notation (SAN), except for disambiguation (a precision on the file or rank of the starting square). Be careful, details are important: If the problem says "4. Ra8", then the problem asks to move a rook to a8 without capture.
The following chess problems look like nothing, but they're often very beautiful, especially the checkmate problems. The first few plies are trivial and omitted. Click on a problem to see the solution.
(all 20 moves of white)
(nothing)
(16 captures of black pawns on the 5th rank)
(9 captures of white pawns on the 5th rank)
3. Qd6+
3. Qe4+
3. Qe5+
3. Qxb8
3. Qxf8+
3... Bf6+
3... Bxb3+
3... Rxe5+
3... Qd4#
4. Ra8
4. Rh8
4... b5#
4... Re1+
4... Re2
4... Qb5#
5. Ng3#
5. Qxe4#
5... Rh1# (featured as ChessBase Christmas 2006 Puzzle 7!)
6. gxf8=N# (found first by Peter Rösler)
(no checkmate problem)
Thanks to Joost de Heer for computing ply 11 with my program on his computer, thereby confirming that gxf8=N# is the unique such problem at ply 11. The computation took about 3 months on a 1.6 GHz Pentium4 computer.
Is there anything else at ply 12 or beyond that would beat the current record gxf8=N#? In 2007 I verified that no such checkmate problem exists at ply 12. This leaves the slim possibility of a non-checkmate problem at ply 12, or of a problem at ply 13 or beyond.
back to Chess Problems by Computer