Selfmate

A selfmate is a category of chess problem with an objective inverted from ordinary chess: White, moving first, must force Black, who is trying to avoid it, to deliver checkmate against White's own king within a stated number of moves. Historically such problems were called sui-mates before the modern term became standard. Solving one requires White to make a forcing sequence of moves that strips away every legal Black reply except ones that end in checkmate, so unlike a conventional mating problem where White wants to deliver mate, the composer's craft lies in engineering Black's forced compliance. The genre sits within the wider tradition of chess problem composition rather than practical over-the-board play, valued by composers and solvers for the counterintuitive logic it demands and the elegance of a position where every one of Black's escapes has been closed off in advance.