Chess Opening Theory/1. e4/1...c6/2. d4/2...d5/3. Nc3/3...dxe4/4. Nxe4/4...Bf5/5. Ng3/5...Bg6/6. h4/6...h6/7. Nf3/7...Nd7/8. h5/8...Bh7/9. Bd3/9...Bxd3/10. Qxd3

= Caro-Kann Defence:Classical Variation = Previously, all three main responses (...Ngf6, ...e6, ...Qc7) were thought to be equivalent, and often transposed to the same position with black castling queenside. Later development saw Black look at castling kingside, but for a while this fell out of favour as White found he could move his knight to e4 or e2, and advance g4, without needing to prepare Rg1. This extra tempo seems to threaten this line as a viable alternative for black, as white can win the race between the white kingside and black queenside attacks. More recent theory, however, has seen Black resurrect ...e6, quite often not castling at all, while the other alternatives remain out of favour.

Theory table
.

1.e4 c6 2.d4 d5 3.Nc3 dxe4 4. Nxe4 Bf5 5. Ng3 Bg6 6. h4 h6 7. Nf3 Nd7 8. h5 Bh7 9. Bd3 Bxd3 10. Qxd3