Pure mate

A pure mate is a checkmating position in chess in which the mated king and all vacant squares in its field are attacked only once, and squares in the king's field occupied by friendly units are not also attacked by the mating side (unless such a unit is necessarily pinned to the king to avoid it interposing to block the check or capturing of mating unit).

Although several famous games ended in them, such as the Immortal Game, Evergreen Game, Peruvian Immortal, and Game of the Century, pure mates are of only incidental interest in practical play, but they are considered by some to add value to a chess problem.

If all units of the mating side, with the possible exception of the king and pawns, are involved in a pure mate, then it is a model mate; if all units of both colours are involved in a pure mate, then it is an ideal mate.

Example

Anderssen vs. Dufresne, 1852

	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

Final position

A pure mate occurred in the Evergreen Game between Adolf Anderssen and Jean Dufresne in 1852; the final position is shown. The black king is attacked only by the bishop on e7; the e7- and g7-squares are attacked only by the pawn on f6; the e8-square is attacked only by the bishop on d7; and the rook on g8 and pawn on f7 which stop the black king moving to those squares are not also attacked by white pieces.

gollark: Google also had that whole thing with tracking locations even when that was disabled.

gollark: So you're just hoping that evil governments will also be incompetent?

gollark: Also, you live in Turkey, which has a kind of evil government, right? If Google cooperated with them, they could probably use that data to track down and/or identify dissidents.

gollark: I think they already use location data to "help" investigate crimes, in ways which tend to implicate innocent people randomly.

gollark: Giving one company access to people's accurate location history, conversations, emails and whatnot could probably lead to problems.

References

Hooper, David; Whyld, Kenneth (1996) [First pub. 1992]. "pure mate". The Oxford Companion to Chess (2nd ed.). Oxford University Press. pp. 326–27. ISBN 0-19-280049-3.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.