1.Kd6-c5 ! zugzwang.
1...Rd2*e2
2.Bb4-c3 threat:
3.Ra1*c1 +
3...Kd1*c1
4.Ra6-a1 #

1...Kd1-e1
2.Ra6-f6 threat:
3.Ra1*c1 #
2...Ke1-d1
3.Sd5-e3 +
3...Kd1-e1
4.Ra1*c1 #

1...Rd2*d3
2.Sd5-e3 +
2...Rd3*e3
3.Ra6-d6 +
3...Re3-d3
4.Rd6*d3 #