This Semi-Slav variation is marked by the moves 6.Qc2 Bd6 7.g4. Black has four traditional responses to 7.g4: 7...h6, Nxg4, Bb4, and dxc4. This variation is credited to Alex Shabalov, with Alexei Shirov playing it for the first time in 1992. The variation is thus often called the Latvian Gambit (somewhat confusing since that name is given to 1.e4 e5 2.Nf3 f5) or the Shabalov-Shirov Gambit. Since the opening's beginning, the most popular response has been 7...dxc4, but at top levels in recent years, the move has been 7...h6. Filtering a largely up-to-date Chessbase Mega 2009 database, I find 50 games with both players greater than 2500 in games played from 2006-2009. The results are (with a Rybka evaluation at 18 ply tacked on):
7...h6, 31x, W: 48.4%, Perf. Elo +29, (0.00) Rybka 3
7...Nxg4, 10x, W:70%, Perf. Elo -147, (0.00) Rybka 3
7...dxc4, 4x, W:37.5%, Perf. Elo +50, (0.09) Rybka 3
7...Bb4, 4x, W:37.5%, Perf. Elo +140, (0.32) Rybka 3
Draw your own conclusions on this sparse sample, but it at least indicates the top players' preference. I have not been able to confirm this preference with the aid of Rybka; however, and I've stood by 7...dxc4 with good results. We'll look at each of Black's responses in turn, beginning here with 7...h6. The conclusion on 7...h6 can be summed up as "solid."
The endgame is highly instructive. Take a look at the position after White's 56th and compare it to the 1949 game that follows.