Accepting the Greek Gift

The "Greek Gift" bishop sacrifice against the castled king with Bxh7+ (or ...Bxh2+ as Black) is a very powerful attacking idea. As with so many such ideas, it is first known to have been played by Greco almost 400 years ago.

But it doesn't always work! For example, in Charbonneau-Al-Ali, Olympiad 2008, the Canadian GM's sac was erroneous; he had failed to anticipate an unusual defensive idea (...Qa5+! followed by ...Qf5!). Vladimir Vukovic, in his classic The Art of Attack in Chess, devotes a whole chapter to exploring the sacrifice and when it does and doesn't work.

Vukovic noted that after the typical 1.Bxh7+ Kxh7 2.Ng5+, Black can play ...Kg8, ...Kg6, and ...Kh6. "These three variations must be carefully examined on every occasion, for if any one of them contains a loophole, the whole combination falls to the ground." In the following game, my opponent surprised me with 11.Bxh7+, rather than the sane 11.cxd4 of Rozentalis-Arias, Olympiad 2008. The sac would have worked like a charm if I had robotically played 12...Kg8, e.g. 13.Qh5 Re8 14.Qxf7+ Kh8 15.Qh5+ Kg8 16.Qh7+ Kf8 17.Qh8+ Ke7 18.Qxg7#. However, 12...Kg6! left him without an effective follow-up and I won quickly.