The queenside break
Attack the d5 pawn and open lines for your queen and rooks.
When Black has a pawn on d5 and you have already played and , you play . That pawn attacks d5 and clears c2, so your queen can now come out via b3 or a4. With you add a second attacker on d5. If pawns are traded, on c4 or on d5, your c-pawn is gone and the c-file has no white pawn in front of your rooks; if Black takes with , you recapture with and the bishop from f1 joins the game. The idea also works when Black starts with and plays later.
1 in 10 masters chooses it here.See dataHide
Over-the-board games, 2300+: 13% of 495. Online, 2200+: 16% of 13,939.