Patterns and Calculation

If we fail to make an idea work, we need to stop and ascertain the cause of the failure (i.e. answer the question 'why?'), and then attempt to correct our design.
Paata Gaprindashvili, Imagination in Chess (2004), 40.

A chess problem that cropped up in tactics training yesterday immediately reminded me of a game I had seen working through the compositions of Gioachino Greco, but the solution in Greco fails. Noting the failure, I considered why it failed and calculated the remedy. The whole process required about 23 seconds.

This elementary exercise serves to supplement my posts, "Patterns and Calculation" (23 December 2016), "Patterns: Some Evidence" (11 January 2017), and to highlight my endorsement of Paata Gaprindashvili, Imagination in Chess (see "Imagination in Chess").

White to move

The position arose in a correspondence game on Chess.com and was presented to me through the tactic trainer there. That game was a Ponziani in which Black blundered early.

Greco's game arose via a King's Gambit. I present it as it appears in Francis Beale, Royall Game of Chesse Play (1656).

Gambett LIII (Greco) [C37]
1656

1.e4 e5 2.f4 exf4 3.Nf3 g5 4.Bc4 h6 5.h4 f6 6.Ne5 fxe5 7.Qh5+ Ke7 8.Qf7+ Kd6 

White to move

9.Qd5+ Ke7 10.Qxe5# 1–0

The checkmate pattern in both games is the same, except that there is an alternative checkmate in the tactics problem if Black moves the king after White's initial move. The key difference, however, is that Black's knight guards e5 in the tactics problem. Hence, applying Gaprindashvili's advice, White must first lure this knight to e5, then execute the winning queen maneuver.

Instant recognition of patterns can be trained and aids in the development of chess strength. The same pattern often occurs in seemingly dissimilar games. Recognizing the pattern offers a plan, but calculation remains a necessary component to verify that the pattern has application.