French defence
1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.e5 c5 5.a3 Bxc3+ 6.bxc3 Ne7 7.Qg4 Qc7 (7...0-0 is possible) 8.Qxg7 Rg8 9.Qxh7 cxd4 10.Ne2 and so on. The play in lines like this is strongly asymmetric: White owns the kingside, and Black owns the queenside.