Rukhlis theme

At least two set play (or try play) mates are transferred to different defences after the key, while the original defences are answered by changed mates.

Scheme:
1.X a 2.A, 1…b 2.B, 1…c 2.A??, 1…d 2.B??
1.Y a 2.C, 1…b 2.D, 1…c 2.A, 1…d 2.B

ideal Rukhlis

Scheme:
1.X a 2.A, 1…b 2.B, 1…c 2.C, 1…d 2.D
1.Y a 2.E, 1…b 2.F, 1…c 2.A, 1…d 2.B

cyclic Rukhlis

Scheme:
1.X a 2.A, 1…b 2.B
1.y b 2.A, 1…c 2.B
1.z a 2.B, 1…c 2.A

distributed Rukhlis

Scheme:
1.X a 2.A, 1…b 2.B
1.Y a 2.C, 1…c 2.A
1.Z b 2.D, 1…d 2.B

or:
1.X a 2.A, 1…b 2.B
1.Y a 2.C, 1…b 2.D
1.Z c 2.A, 1…d 2.B

extended Rukhlis

Scheme:
1.X a 2.A, 1…b 2.B, 1…c 2.C
1…d 2.A??, 1…e 2.B??, 1…f 2.C??
1.Y a 2.D, 1…b 2.E, 1…c 2.F
1…d 2.A, 1…e 2.B, 1…f 2.C

condensed Rukhlis

Scheme:
1.X a 2.A, 1…b 2.B, 1…c 2.B??
1.Y a 2.C, 1…b 2.A, 1…c 2.B

Żuk, Henryk
The Observer, 1960

mate in 2 moves