Fata Morgana
The side to move could reach the goal in fewer moves than stipulated if the move were made by the other side, but lacks a waiting move.
This is the selfmate theme, though the term can also apply to other genres.
⧖ The term was coined after the book with same title, compiled and edited by Dr. Eduard Birgfeld (1887-1939), Berlin 1922. The book contains over 900 selfmates, of which some 700 were originals.
See also: Apparent mate; Short set play.
Loewenton, Leon
Die Schwalbe, 1960
1st Prize
h#5* (7+10)
1...Bc1#
1.Kb2
Bc1+
2.Kxc3
Bb2+
3.Kxb4
Bc3+
4.Ka3
Bd2
5.b4
Bc1#