Editing Babson task (section)

{{Short description|Type of chess problem}}
A '''Babson task''' (or simply '''Babson''') is a {{chessprobgloss|directmate}} [[chess problem]] with the following properties:

#White has only one {{chessprobgloss|key}}, or first move, that forces [[checkmate]] in the stipulated number of moves.
#Black's defences include the [[Promotion (chess)|promotion]] of a certain [[Pawn (chess)|pawn]] to a [[Queen (chess)|queen]], [[Rook (chess)|rook]], [[Bishop (chess)|bishop]], or [[Knight (chess)|knight]]. (Black may have other defences as well.)
#If Black promotes, then the only way for White towards a forced checkmate in the stipulated number of moves is to promote a pawn to the same piece to which Black promoted.

{{ill|Joseph Ney Babson|it}} (1852–1929), the task's eponym, first conceived of the task in 1884, but never solved it.<ref>
{{cite web
|url=https://timkr.home.xs4all.nl/admag/kazan.htm
|title=De man die de Babson task maakte
|author=Tim Krabbé
|author-link=Tim Krabbé
|language=Dutch
}}
</ref>
To devise a satisfying Babson task is regarded as one of the greatest challenges in [[Chess composer|chess composing]]. For almost a century, it was unknown whether such a task could exist.

The Babson task is a special form of [[Allumwandlung]], a chess problem in which the solution contains promotions to each of the four possible pieces. Such problems were already known when Babson formulated his task.
{{algebraic notation|pos=toc}}