Ruy Lopez that after the common retreat 4.Ba4, Black will have the possibility of breaking a future pin on his by playing ...b5. White must take some care not to fall into the Ruy Lopez, Noah's Ark Trap, in which Black traps White's on the b3-square with a ...a6, ...b5, and ...c4 pawn advance on the . Ercole del Rio, in his 1750 treatise "Sopra il giuoco degli Scacchi, Osservazioni pratiche dell'anonimo Modenese" (On the game of Chess, practical Observations by an anonymous Modenese), was the first author to mention 3...a6. However, the move became popular after it was played by Paul
Ruy Lopez move carries no immediate threat, Black can respond in a wide variety of ways. Traditionally, White's objective in playing the Ruy Lopez is to spoil Black's pawn structure; either way Black recaptures following the exchange on c6 will have negative features for him, though he thereby gains the . However, in modern practice, White does not always exchange bishop for knight on c6, preferring the retreat 4. Ba4 if chased by 3...a6. The theory of the Ruy Lopez is the most extensively developed of all open games, with some lines having been analysed well beyond move thirty. At nearly every