Jerome Gambit: Give Me A Break

I have maintained The Database of Jerome Gambit games to help me get a sense of how certain lines or moves succeed or fail - from a practical (i.e. over-the-board play) point of view.

I have used chess analysis engines (currently Stockfish 8) to get a sense of how certain lines or moves are "objectively" strong or weak.

It is a joy when both the practical and the analytical agree. It can be confusing when they don't. Take the following game. It left me a bit confused...

Petasluk - givemeabreak
5 0 blitz, FICS, 2017

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ 

4...Kxf7 5.Nxe5+ Nxe5 6.Qh5+ Kf6 

Including this game, Petasluk has reached this position 7 times according to The Database (which, I admit, need some updating). Before this game he was 2-1 with the followup 7.Qf5+ and 2-1 with 7.f4. This compares with statistics from the whole Database - White scores 80% (35 games) with 7.Qf5+ and 80% (10 games) with 7.f4.

So, from a practical point of view, 7.Qf5+ and 7.f4 are both good move choices, according to Petasluk's experience; and both are excellent choices from the experience of those represented by The Database.

7.f4 

So, no surprise here.

Yet the computer analysts, starting with Stockfish 8, leap directly for the straightforward 7.Qf5+ Ke7 8.Qxe5+ Kf8 9.Qxc5+ picking up the two sacrificed pieces.

Why the discrepancy?

7...g6

Well, here is one reason: the defender in this game is human, and humans make mistakes. The alternative 7...Nc6, withdrawing the attacked piece, allows White to only recover one of his sacrificed pieces:  8.Qf5+ Ke7 9.Qxc5+ Kf7, with pressure on the enemy King, but not full compensation for his offerings.

8.Qxe5+ Kf7 9.Qxh8 Black resigned 

Well, it looks like "Practical Experience 1, Computer Analysis 0".

But that is not the whole story. A number of Petasluk's games continued from the above "final" position:

9...Nf6 (9...d6 10.Qxh7+ Kf8 11.d3 Qf6 12.Qxc7 Be3 13.Nc3 Qxf4 14.Rf1 Qxf1+ 15.Kxf1 Bxc1 16.Rxc1 Black resigned, Petasluk - douthy, FICS, 2015; or 9...Qe7 10.Qxh7+ Kf6 11.Qxg8 Qxe4+ 12. Kd1 d5 13.Qh8+ Kf5 14.Qh3+ Kxf4 15.Rf1+ Kg5 16.Qg3+ Bg4+ 17. Rf3 Re8 18.c3 d4 19.h3 Qe2+ 20.Kc2 d3+ 21.Rxd3 Qd1 checkmate, Petasluk - kosten, FICS, 2013) 10.Qxd8 Black resigned Petasluk - skaks, FICS, 2015 and Petasluk - kaliz, blitz, FICS, 2014 Be7 11. Qh8 11... b6 12. e5 Bb7 13.Qxa8 Bxa8 14. exf6 Bxf6 15. O-O Be4 16. d3 Bc6 17. Nc3 Black resigned, Petasluk - TaccyChan, FICS, 2007.

That's 4 wins and 1 draw. More support for practical considerations.

But I expect the "Wait 'til next time!" bunch will want to look closer at 7.Qf5+.

(Where did the "extra" games come from? Petasluk - TaccyChan, FICS, 20017; Petasluk - Kosten, 2013 and Petasluk - douthy, FICS, 2015; all transposed from 6...Ke6.)