Mate in four.

Doggy_Style

 
White to play and mate in four.
Doggy_Style

Just too difficult....

bigpoison

easy

pie314271

I think I may know the moves...

Doggy_Style
y2721 wrote:

I think I may know the moves...

No engines Wink

cobra91

It certainly wasn't easy, but I managed to solve it. The key to finding the first move is to notice how all of the obvious tries fail. 1.Nc4? fails to 1...c2, while 1.Ne4 fails to 1...Kd3. Also, 1.Qb5?! (cutting off d3) is a move too slow after 1...c2 2.Ne4 c1=Q 3.Qd7+ Ke5 4.Qd6+ Kf5 5.Qf6#. It was this last variation in particular that led me to the correct line:

1.Qd7! Kd3 2.Qf5+ Kd2 (2...Kd4 3.Nb5#) 3.Nc4+ Kc1/d1/e1 4.Qxb1#

1...Kc5 2.Nc8! Kb4 (else 3.Qd6+ Kb5 4.Qb6#) 3.Qa4+ Kc5 4.Qc4#

1...Ke5 2.Ne8! Kf4 (else 3.Qd6+ Kf5 4.Qf6#) 3.Qg4+ Ke5 4.Qe4#

1...c2 (or any other move) 2.Ne4+ Ke5 3.Qd6+ Kf5 4.Qf6#

The middle two variations are of course the most thematic, and they are mirror images of each other. A well composed problem.  :)

Doggy_Style

Apologies for just noticing that some brave soul had solved this beast. Well done cobra91! a trophy wings its way towards you.