Selfmate

A selfmate is a chess problem in which White, moving first, must force the unwilling Black to deliver checkmate within a specified number of moves. Selfmates were once known as sui-mates.

Example

The problem shown is a relatively simple example. It is a selfmate in two by Wolfgang Pauly[1][2] from The Theory of Pawn Promotion, 1912: White moves first and compels Black to deliver checkmate on or before Black's second move.

Wolfgang Pauly, 1912
abcdefgh
8
a8 white king
b8 white bishop
f8 white knight
a7 white pawn
c7 white pawn
e7 black pawn
g7 white pawn
f6 white pawn
h6 black king
e5 white pawn
h5 black pawn
h4 white pawn
g2 white bishop
h1 black bishop
8
77
66
55
44
33
22
11
abcdefgh
Selfmate in two

If White can leave Black with no option but to play Bxg2#, the problem is solved.

  • White might try moving the bishop, but this is no good, as it will allow Black to play a non-capturing bishop move himself, delaying the mate beyond move two;
  • moving the knight allows the king to move;
  • 1.e6 allows 1...exf6 and 2...f5;
  • 1.f7 or 1.fxe7 allows 1...Kxg7;
  • 1.g8=Q or 1.g8=R are no good after 1...Bxg2+ 2.Q/Rxg2;
  • 1.g8=N# checkmates Black, which is entirely wrong;
  • 1.g8=B is also no good, since after 1...exf6 2.exf6 Bxg2+ the bishop can interpose with 3.Bd5.

The only move by which White can force Black to deliver checkmate on or before move two is 1.c8=N. There are two variations:

  • 1...exf6 2.exf6 Bxg2# is a selfmate;
  • 1...e6 allows 2.g8=B (the e6 pawn blocks 3.Bd5), forcing 2...Bxg2# and selfmate.

Note that only a promotion to a knight works on move one: any other piece would be able to interpose after 1...Bxg2+.

Record problems

Karlheinz Bachmann (version by Christopher Jeremy Morse), 2006
abcdefgh
8
g8 white king
b7 black knight
c6 black pawn
a5 black pawn
c5 white pawn
g5 black knight
a4 white bishop
e4 white queen
g4 black pawn
h4 white pawn
a3 black pawn
f3 white pawn
h3 black pawn
a2 black pawn
b2 black bishop
g2 black pawn
h2 black rook
a1 black rook
c1 black king
h1 black bishop
8
77
66
55
44
33
22
11
abcdefgh
White to play, selfmate in 203

The current record for the longest selfmate problem is a selfmate in 203, composed by Karlheinz Bachmann and Christopher Jeremy Morse in 2006.[3] The puzzle is based on a 1922 342-move composition by Ottó Titusz Bláthy, which was later found to be cooked.

Prior to December 2021, the record for the longest selfmate problem was a 359-move problem, created by Andriy Stetsenko in 2016.[4] Unfortunately, this problem was later found to be cooked, as a shorter solution exists.

Variations

A derivative of the selfmate is the reflexmate, in which White compels Black to give mate with the added condition that if either player can give mate, they must (when this condition applies only to Black, it is a semi-reflexmate). There is also the maximummer, in which Black must always make the geometrically longest move available, as measured from square-centre to square-centre; although this condition is sometimes found in other types of problems, it is most common in selfmates. Another variation is the series-selfmate, a type of seriesmover in which White makes a series of moves without reply, at the end of which Black makes one move and is compelled to give mate.

See also

References

  1. Pauly selfmate
  2. "W. Pauly". Archived from the original on 2012-03-02. Retrieved 2010-01-03.
  3. Morse, Christopher Jeremy (July 2006). "NINTH UPDATE OF CHESS PROBLEMS: TASKS AND RECORDS". The Problemist. 20 (480): 431.
  4. "Award in Jubilee Tourney" (PDF). SuperProblem. Retrieved 12 August 2021.

Further reading

  • Chlubna, Friedrich (1995). Das Matt des weissen Königs. Vienna: Chlubna. ISBN 3-9500310-3-0.
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