1.Qa5+Kb8
2.Qb6+Ka8
3.Nb5!
Threatening Nc7#
3...Qb7
4.Qd8+Qb8
5.Qd5+Qb7
6.Qa2+Ba4
6...Kb8 loses more quickly, viz: 7.Qg8+ Qc8 8.Qg3+ Ka8 (If 8...Kb7 9.Nd6+) 9.Qa3+ Kb8 10.Qa7#
7.Qxa4+Kb8
8.Qf4+Ka8
9.Qf8+Qb8
10.Qf3+Qb7
11.Qa3+Kb8
12.Qf8+Qc8
13.Qf4+Ka8
14.Qa4+Kb8
15.Qa7#
Gunst (1926)