In an interesting game that I have found from Chess.com, Black actually had a way to draw the game even after the sacrifice, but the subsequent variations were too complicated and he eventually slipped. The credit for this game must go to Loomis (http://www.chess.com/members/view/Loomis), whose annotations I shall include in the KnightVision viewer below:
1. d4 d5
2. c4 e6
3. Nc3 Bb4
4. e3 Ne7
5. Nf3 Nbc6
6. Bd3 Bxc3+
7. bxc3 Bd7
8. O-O O-O (D)
|Position after 8... O-O|
9. Bxh7+ Kxh7
10. Ng5+ Kg6
This is the variation where things get tricky for White. On the other hand, going back to g8 would have led to mate: 10... Kg8 11. Qh5 Re8 12. Qh7+ Kf8 13. Qh8+ Ng8 14. Ba3+ (or 14. Nh7+ Ke7 15. Ba3+ Nb4 16. Bxb4+ c5 17. Bxc5#) 14... Re7 15. Nh7+ Ke8 16. Qxg8#
11. Qg4 e5?
The resultant lines are too complicated for Black, who failed to see the variation that could have led to a draw: 11... f5 12. Qg3 f4 13. exf4 Nf5 14. Qg4 Nh6 15. Qg3 Nf5 where Fritz places the position as equal for both sides.
12. Ne6+ Kf6
13. f4 e4 (D)
|Position after 13... e4|
14. f5! Bxe6 (14... fxe6 15. fxe6+ Nf5 16. Qxf5+ Ke7 17. Ba3+) 15. fxe6+ Nf5 16. Qxf5+ and the attack continues.
14... fxe6 15. dxc6 Bxc6 would have allowed Black to equalize quickly and retain his extra material (Fritz gives this position a -1.83 score in favour of Black!)
15. f5 fxe6
16. fxe6+ Ke7
17. Ba3+ Ncb4
18. Qxg7+ Kxe6?
19. Qe5# (D)
18... Kd6 was more resilient but Black still won't survive for long: 19. Bxb4+ (19... Nxb4 20. Qe5+ Kc6 21. Qc5#) 19... Kc6 20. Bxf8 and Black can resign.
|Position after 19. Qe5#|
The unusually high number of question marks in the above annotations is enough to testify to just how tricky it is to calculate such variations!
In the next example, the variations with Kg3 are less tricky but still require some thinking:
|Example 2: Variations with Kg3|
2. Kxh2 Ng4+
Once again, this is the variation which leads to very tricky calculations. On the other hand, 3. Kg1 Qh4 and 3. Kh3 Nxf2+ both win easily for Black (you can tell why!).
After 4. Kf3 Nxe3 5. fxe3 (5. Bxe3 Qg4#) 5... Bg4+ Black wins the Queen.
Once again 5. Kf3 leads to 5... Nxe3
6. Kf4 h6!
6... Qd6+?! 7. Kf3 gives the White king a better chance of escaping.
7. Qe1 Nh2 8. Qh4 Qd6+ 9. Kxf5 g6#
8. Nxe4 Rxe4+
Black has regained his material with an overwhelming attack; checkmating White should now only be a matter of time and technique.
In our last example, White appears to have a promising attack, but the variation with Kh6 poses the greatest challenge:
|Example 3: White has his tricks, but do does Black!|
1. Bxh7+ Kxh7
2. Ng5+ Kh6!
The best way for Black to fight back. By now you should know what happens after 2. Kg8 or 2. Kh8, while after 2... Kg6 3. Qd3+ f5 4. Qg3 f4 5. Qg4 Kh6 6. Nxe6 White can keep up the attack.
3. Qd2 Qe7
4. Nxe6+ Kh7
5. Nxf8+ Rxf8 (D)
|Position after 5... Rxf8|
White has regained his material, but Black manages to spring back from his seemingly lost position.
In many games featuring the Greek Gift sacrifice, the variations with Kg6/Kg3 and Kh6/Kh3 are often the trickiest to calculate, and after looking through these examples it shouldn't be difficult to tell why! The lesson to be learned here is: When planning an attack on the castled king, especially one involving a Greek Gift sacrifice, the art of calculating tactics is a crucial component for success. The greatest GMs are able to do this and at the same time manage their time control well; are you able to do it?
In the next article, we will look at more unorthodox examples of Greek Gift sacrifices that have occurred in actual gameplay.
Part 1: http://nushsblackknights.blogspot.com/2014/07/when-in-doubt-bxh7-part-1.html
Part 2: http://nushsblackknights.blogspot.com/2014/07/when-in-doubt-bxh7-part-2.html
Part 3: http://nushsblackknights.blogspot.com/2014/07/when-in-doubt-bxh7-part-3.html
"How to calculate Chess Tactics" by Valeri Beim
"Art of Attack in Chess" by Vladimir Vukovic