Anomaly

Intrigued by yesterday's Jerome Gambit Declined (1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ Kf8/Ke7) game (see "Tumbling Dice"), I thought I'd take a look at the line in The Database and see what up-to-date data I could drum up.

I was surprised to see that White, ahead a pawn and having prevented Black from castling, only scores 58% in 238 games. Admittedly, that's better for White than the straight Jerome Gambit line – 44% in 8,737 games – but it still seems light.

(Perhaps one must take into account the level of play, and Geoff Chandler's "blunder table".)

Breaking it down was not much help.

In 205 games, when Black declined the Bishop sacrifice with 5...Kf8, White scored 57%. Immediately removing the White Bishop from danger or exchanging it off – what would appear to be the simplest and best plan for the first player – did not matter a whole lot. In 51 games White played 6.Bxg8, scoring 63%. This was better than the 25 games in which White played 6.Bb3, scoring 56%; and the 18 games where White played 6.Bc4, scoring 53%. However, only one of those percentages is an improvement on the core 57%.

(We seem to have hit another one of those Jerome Gambit anomalies: by playing a "worse" line, White, apparently, scores "better" – or at least not any worse.) 

In the 33 games where Black played 5...Ke7, however, White scored 71%. That should be an indication for Black – although accepting the Bishop with 4...Kxf7 remains the best idea.