A Recent Example of the Classic B Sacrifice

     I don't often post recent games, but the following game which was played in the recently concluded St.Petersburg tournament caught my attention. The event, a 12-player round robin, was played from March 18th to March 23rd. 

Final standings: 
1) Evengy Alekseev 8.0 
2) Evengy Levin 7.0 
3-4) Ilya Duzhakov and Alexei Saveliev 6.5 
5) Ilya Azimov 5.5 
6-7) Sergei Lobanov and Kirill Alekseenko 5.0 
8-12) Vasily Usmanov, Dmitry Fraiman, Artur Dilmukhametov, Maksim Schekachikhin and Denis Pershin 4.5 

     First of all, the opening was an old favorite, the Winawer variation of the French Defense and secondly, there was a Bishop sacrifice on h7. You don't often see a sacrifice like that in modern games, especially in games between 2400s; modern players are just too alert to the possibility. 
     The old Bxh7+ trick is one of the oldest and most explored of all the sacrifices and it illustrates the weakness of h7 and f7. Max Euwe called it a “break up combination” because the King is deprived of its Pawn protection and he pointed out that these combinations will only be successful if the number of attacking pieces greatly exceeds the number of defending pieces. After the sacrifice the number of pieces left must be sufficient to either mate or gain some other decisive result. It is particularly important for the attacker to have at least one Rook on an open file which can quickly join the attack. In the case of a sacrifice on h7 the following conditions must be present: 

1) a Rook must be immediately available 
2) the enemy must be unable to defend his King 
3) the King cannot escape via f8 
4) the refusal of the sacrifice must have serious disadvantages 
5) the attacker must be able to get a Knight to g5 
6) the material situation at the end of the combination must be favorable.