Normal Variation, .. a6 Sideline

This branch of the Normal Variation arises when Black answers 5. Bxc4 with 5...a6. That move also belongs to the main line and usually transposes after 6. O-O c5. White's 6. Nc3 instead permits 6...b5 at once, which drives the bishop from c4 and claims queenside space before Black has committed to ...c5. Material is level. With the c- and d-files half-open, Black keeps the standard Queen's Gambit Accepted aim of challenging White's d4-e3 center with ...c5.

The bishop must retreat, and where it goes shapes the middlegame. 7. Bd3, pointing at the kingside, is chosen in about half of games. 7. Bb3, which stays on the a2-g8 diagonal, and the more modest 7. Be2 account for most of the rest. The engine rates all three as roughly equal. On Lichess the results are close to even, with Black winning slightly more often than White. The line is a moderately common choice rather than a heavily analyzed main road.