Opening Exchange Sac [B7x]
One of the best known opening sacrifices is the move ...Rxc3 against the Yugoslav Attack in the Dragon Variation of the Sicilian Defense. The idea has several motivations and works in many positions. Who played it first at the international level and when was it played?
After a few minutes search, the earliest example I could find is shown in the diagram. It is game no.1 in Karpov's 'Best Games' (Batsford, 1996). The opening moves were: 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6 6.Be3 Bg7 7.f3 O-O 8.Bc4 Nc6 9.Qd2 Qa5 10.O-O-O Bd7 11.h4 Ne5 12.Bb3 Rfc8 13.h5 Nxh5 14.Bh6 Bxh6 15.Qxh6. It is arguable whether we are still in the opening here.
The players have just exchanged Bishops on h6. Now Black played 15...Rxc3 and Karpov wrote:
The standard exchange sacrifice in the Dragon. On the one hand Black protects himself from the Knight lunging onto d5, and on the other hand he shatters the enemy King's fortress.
The note indicates that the idea was already well known at the end of the 1960s. The sacrifice is even stronger when the dark-squared Black Bishop is still on the long diagonal.
Moscow 1968-69
Gik, Evgeny
Karpov, Anatoli
(After 15.Qd2-h6(xB))
[FEN "r1r3k1/pp1bpp1p/3p2pQ/q3n2n/3NP3/1BN2P2/PPP3P1/2KR3R b - - 0 15"]
The game continued 16.bxc3 Qxc3. Karpov again:
The Black Queen here is occupying an ideal position to generate threats to the White King, and it is difficult to believe that this move can already be a decisive mistake. Either 16...Nf6 or 16...Rc8 was necessary.
Karpov is often spare with his analysis and doesn't explain why those two moves are better. We have to work it out for ourselves. He played 17.Ne2, and awarded himself a '!':
In the event of 17.Kb1 a5, Black obtains fair counterchances. However, the modest Knight retreat to e2 is extremely unpleasant for Black. The Knight deals with the problem of ousting the Queen beautifully, and simultaneously joins in the attack on the Kingside.
Now the game continued 17...Qc5 18.g4 Nf6 19.g5 Nh5 20.Rxh5 gxh5 21.Rh1 Qe3+ 22.Kb1 Qxf3 23.Rxh5 e6. Here he spent a page and a half explaining why 23...Ng6 also lost. Contrary to popular opinion, he was a wonderful tactician.
To play through the complete game see...
Anatoli Karpov vs Evgeny Gik, 05, Moscow ch-stud 1968
http://www.chessgames.com/perl/chessgame?gid=1067442
...on Chessgames.com.