C69 Ruy Lopez: Exchange Variation

White gives up the bishop for a knight on move four and castles, reaching the Ruy Lopez Exchange Variation with 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6 dxc6 5.O-O. Code C69 covers Black's reply 5...f6, the Gligoric line, which guards e5 with a pawn and keeps the bishop pair. White usually opens the centre with 6.d4 exd4 7.Nxd4, aiming for an endgame where the 4-v-3 kingside majority can create a passed pawn while Black's doubled c-pawns cannot. After 7...c5 Black drives the knight away and uses the two bishops and open files for active piece play.