A selfmate is a chess problem in which White, moving first, must force Black to deliver checkmate within a specified number of moves. Selfmates were once known as sui-mates.
A selfmate is a chess problem in which White, moving first, must force Black to deliver checkmate within a specified number of moves. Selfmates were once known as sui-mates.
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.
| a | b | c | d | e | f | g | h | ||
| 8 |         | 8 | |||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h | ||
If White can leave Black with no option but to play Bxg2#, the problem is solved.
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:
Note that only a promotion to a knight works on move one: any other piece would be able to interpose after 1...Bxg2+.
| a | b | c | d | e | f | g | h | ||
| 8 |    | 8 | |||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h | ||
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.[ citation needed ]
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.
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.