1987 Szachy
1. Prize
1.Qe6? ~ 2.Qd6# 1...Sc4! (2.Be6?)
1.Be6? ~ 2.Bd5# 1...Bc4! (2.Se6?)
1.Se6? ~ 2.Sd4# 1...Rc4! (2.Qe6?)
1.Bf5! ~ 2.Qd5 Kd5 3.Bd5# 1...Sc4 2.Be6 ~
(2..Bc4?) 3.Bd5# 1...Bc4 2.Se6 ~ (2..Rc4?)
3.Sd4# 1...Rc4 2.Qe6 ~ (2...Sc4?) 3.Qd6#
white self-obstruction, black self-obstruction
pieces move to one square, dual avoidance
3# 10+14 id=76