Daily chess puzzle: Check Mate #410(2)

Another puzzle from Dragoslav Andric’s 1981 book “Matni Udar”.

What move did the players miss in yesterday’s puzzle?

Nikitin v Kuznjecov, USSR 1975

The game continued

1 Rc6+ Kc6

2 Rc1+ Kd6

3Qe5+!! fe

4 de+ Kd7[]

5 Bb5 mate

Solution

In yesterday’s puzzle, I said that the only thing humans had to worry about is whether there was a win in all lines after 1 Rc6+ Kc6 2Rc1+.

The solution shows the mating lines are based on control of the a4-e8 diagonal (Bb5+ or Qb5+, control of the c line, and a nasty on e5: Qe5/ de5.

Komodo shows 2 Rc1+ as winning, but 2 Qc2+!! as mate in 7.

It took a moment to appreciate why: from c2, the Queen has access to c5, checking on that diagonal, and can be supported by Ba6-b5+; and the Q looks all down the c line, whilst the Pd4 controls e5. The Rh1 isn’t needed.

(The mate in 7 happens if Black throws his knights and queen into the path of the Queen)

An interesting example of the automatic human move, of bringing one more piece into the party, as being inferior to precision play.

FEN
3r3r/p3q2p/Bnk1pp2/3n1p2/3P4/5NP1/PPQ2P1P/1K5R b – – 0 2 (after Qc2+)