A classic Johandl, illustrating the standard more-move structure
involving a mainplan which will only work after a foreplan has
eliminated a defence.
The black rook defends both b4 and e7. An immediate attempt to break the focus by 1.Rc7? fails to 1...Bf8! so this defence must be eliminated.
1.Sa5 (threat 2.Rd8+) Rd7 2.Sc4 (threat 3.Sb6) Rb7 3.g5 (threat 4.Se3) Bxg5
Now the knight retraces his steps 4.Sa5 (threat 5.Rd8+) Rd7 5.Sc6 (threat 6.Sb4) Rb7
and the mainplan can safely be played 6.Rc7 (threat 7.Se7) Rxc7 7.Sb4
A perfectly constructed problem.