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

= Ruy Lopez, Barendregt Variation =

Nxe5 is now a threat, because after Qd4, forking the knight and a pawn, Nf3, attacking the queen, Qxe4??, capturing the pawn, there is Re1! pinning the queen to the king. At this point, there are several moves, for example Bg4, pinning the knight, Bd6, protecting the pawn and developing the bishop, f6, also protecting the pawn and Qd6, protecting the pawn again. Bg4 is the most aggressive, pinning the knight, while the supporting Bd6 is also good. f6 looks ugly, but is playable now that white's light squared bishop is off the board.