Chess Opening Theory/1. e4/1...Nc6/2. d4/2...d5/3. Nc3/3...a6/4. exd5/4...Nb4/5. Bc4/5...Nf6

= Nimzowitsch Defence = White now has a number of viable options against black. 6. Bg5 Bg4 7. f3 Bf5 8. Bb3 Nbxd5 9. Nxd5 Nxd5 and White cannot easily prove an advantage. 6. Bf4 Bf5 7. Bb3 Nbxd5 8. Nxd5 Nxd5 9. Bg3 e6 with equality. 6. Nf3 Bf5 7. Bb3 Nbxd5 8. Nxd5 Nxd5 9. 0-0 e6 is also equal.