White to play and win – forced mate in 5
A Calitz v L Bouah 2000
Knowing that the problem is a mate in five, one has to look for forced lines. There are a few random checks which need to be looked at, such as 1 Rd4+?? 1 Qc6+?? 1 Re6+??, but one stands out as needing to be signed: 1 Nb5+!
Black's play is forced: 1…cb 2 Qa6+ Kc7 (2…Bc6 3 Qc6 mate) 3 Qa7+ Kd6 (3…Kc8 4 Qb7 mate) 4 Qb6+ Bc6 5 Qc6 mate.
A nice exercise, good practice for similar cases where you know there is a mate on board, just can't immediately find it.