Solution:

1. Se7 ! threat: 2. Sxc6 Qxc6 3. Qxc6+ Kb8 4. Bh2 ! a4 5. Qxc7+ Ka8 6. Qb8 #

1....Qxe7 2. Qxc6+ Kb8 3. Qb5+ Ka8 4. Qxa5+ Kb8 5. Sd7+ !

a) 5....Bxd7 6. Qa7+ Kc8 7. Qa8 # Pure mate whith one selfblock.

b) 5....Kb7 6. Qb5+ switchback Ka8 7. Qb8 #

Thematic try:

1. Se5 ? Same threat.

1....Qxe5 ! 2. Qxc6+ Kb8 3. Qb5+ Ka8 4. Qxa5+ Kb8 5. Sd7+ ! Kb7 ! and now the difference

with bQ of e5 instead of e7, 6. Qb5+ is not possible; 6. Sxe5 ? c5 ! 7. ?

Decoy sacrifice by white Knight with a 'small difference' between actual play and thematic try only

seen after black 5 th move.

Other try:

1. Sf8 ? z a4 ! 2. Se6 ! threat: 3. Sc7+ Ka7 4. Se4+ Sd4 5. Bxd4 #

2...Qxe6 3. Sxe6 Bxe6 4. Qxc6+ Kb8 5. Bh2 Ka7 ! 6. Bxc7 and 7. ?