Chess Opening Theory/1. e4/1...c5/2. Nf3/2...d6/3. d4/3...cxd4/4. Nxd4/4...Nf6/5. Nc3/5...a6/6. Bg5/6...e6/7. f4/7...b5/8. e5/8...dxe5/9. fxe5/9...Qc7/10. exf6

=Polugaevsky Variation=

Moves : 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5. Nc3 a6 6.Bg5 e6 7.f4 b5 8.e5 dxe5 9. fxe5 Qc7 10. exf6

Now Black has a logical move which explains the move 9...Qc7:

/10...Qe5+/

Indeed, after this move Black will capture a figure : Bishop (in the main line) or a Knight. So, the material will be recovered.

Theory table
.

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 e6 7. f4 b5 8. e5 dxe5 9. fxe5 Qc7 10. exf6