Allumwandlung

Niels Høeg, 1905

	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

Mate in three

Allumwandlung ([ˈalʊmˌvandlʊŋ], German for "complete promotion", sometimes abbreviated AUW) is a chess problem theme where, at some stage in the solution, a pawn (or sometimes pawns) is promoted variously to a queen, rook, bishop, and knight. Allumwandlung's main requirement is promotion, either a white pawn or a black pawn. A Babson task may appear if both pawns are spotted in an individual problem, corresponding one another.

Example

The diagram shows a chess problem with Allumwandlung composed by Niels Høeg and first published in 1905. White to move and mate in three. The key move (White's first move) is 1.f7, and depending on how Black defends, White promotes to either a queen, a rook, a bishop or a knight on move two. The lines are:

• 1... e4 2. f8=Q any 3. Qe7/Qf6#
• 1... Kd6 2. f8=Q+ Kc6 3. Qc5#
• 1... exf4 2. f8=R Kd6 3. Rf6#
• 1... exd4 2. f8=B Kf6 3. Ra6#
• 1... Kf6 2. f8=N exd4 3. Rf7#

The importance of White's underpromotions can be understood by considering what happens if White promotes incorrectly:

• After 1...exf4 or 1...exd4 2.f8=Q?? is stalemate, as black no longer has a legal move to play.
• After 1... exf4, 2. f8=B?? is stalemate.
• Any other promotions will not allow mate on the third move. For example, 1... Kf6 2. f8=Q+ Kxg6: there is no knight to defend the g6 pawn. Or, 1... Kd6 2. f8=R Kc6 and there is an escape on b5.

References

Bibliography

• Hooper, David; Whyld, Kenneth (1992). "Allumwandlung". The Oxford Companion to Chess (2nd ed.). Oxford University Press. ISBN 0-19-280049-3.