1. Qd3+

 I. 1 ... Ke7 2. Qh7+ Kd6
   [2 ... Kf8 3. Qf7#]
   [2 ... Kf6 3. Qh8+ Kf5 4. Bg6+ Kf4 5. Qh2+ +-]
   3. Qc7+ Kd5 4. Qc5+ Ke4 5. Qc2+

  Ia. 5 ... Kf4 6. Qh2+ Ke4
[6 ... Kf5 7. Bg6+ Kf6 8. Qh8+ +-]
7. Bg6+ Kd5 8. Qa2+ Kd6 
[8 ... Kd4 9. Qb2+ Kd5 10. Qb5+ Kd4 11. Qd3#]
 9. Qa3+ Kd7
[9 ... Kd5 10. Qc5#]
10. Qa4+ Kd6 11. Qc6+ Ke7 12. Qe8+ Kf6 13. Qh8+ +-

Ib. 5 ... Ke3 6. Qe2+ Kd4 7. Qb2+ Ke4
[7 ... Kd5 8. Bf3+ Kd6 9. Qa3+ Kd7 10. Bc6+ Kd8 11. Qf8#]
8. Bg6+ Kf4 9. Qh2+ +-

Ic. 5 ... Kd5 6. Bf3+ Kd4
[6 ... Kd6 7. Qc7#]
7. Qb2+ +-
 

II. 1 ... Qd5 2. Qc3! Qf5
    [2 ... Qxh5 {or Qg5} 3.  Qc7+ Kd5 4. Qc5+ +-]
    [2 ... Qa2 3. Qc5+ Kd7 4. Qc7#) (2 ... Ke7 3. Qg7+ Kd6 4. Qc7#]
3. Qc7+ Kd5 4. Qc5+ Ke4 5. Bg6! Qxg6 6. Qc2+ +-