411 REFERENCE · Wikibooks
Chess/Puzzles/Directmates/Two-move 1/Solution
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
The solution is: 1. Qa2
nl ql nd kd pl pl kl Starting position.
nl nd kd pl pl kl ql 1. Qa2
kd xx nd pl pl kl ql If 1... Kxa8 then 2. c8Q#
nl nd pl pl kd xx kl ql If 1... Kc6 then 2. Qd5#
nl xx kd pl pl nd nd kl ql If 1... Nb5 or 1... Nc6 then 2. c8Q#
If 1... Nc8... 2. d8=N#
8 nl nd nl 7 kd pl 6 5 4 kl 3 2 ql 1 40
Other attempts
nl xx xx ql nd kd pl pl kl xx
The move 1. Qb3+ fails because the line 1...Nb5 2. Qxb5+ Kxa8 is mate in three, not two.
Likewise 1. Qb8+ fails to Kc6 2. Qb6+ Kxd7
And 1. c8=Q+ Nxc8 2. dxc8=Q+ Ka7 3. Qf7# is also one move too slow.