Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...a6/4. Bxc6/4...dxc6/5. d4/5...exd4

= Ruy Lopez: Exchange Variation = The best move for white here is 6.Qxd4. This leads to 6.- Qxd4 7.Nxd4. This line is thought to slightly favor black. 6.Nxd4?! is bad because of 6.- c5! and after 7.Nb5 or 7.Nb3, black shall play Qxd1+!, which will give him an advantage.