Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...f5/4. Nc3/4...fxe4/5. Nxe4/5...d5/6. Nxe5/6...dxe4/7. Nxc6/7...Qg5/8. Qe2/8...Nf6/9. f4/9...Qxf4/10. Ne5/10...c6/11. d4/11...Qh4/12. g3/12...Qh3/13. Bc4

13...Be6 is necessary to deny White access to the f7 square while keeping e4 nailed down. It has the pleasant side-effect of getting another piece off the back rank.