Austrian Attack, Salvio Countergambit

The Salvio Countergambit arises from the Austrian Defense, 1. d4 d5 2. c4 c5, a symmetrical reply that traces back to Alessandro Salvio in 1604 and was later studied by the Austrian players Hans Haberditz, Hans Müller and Ernst Grünfeld. When White takes on c5 with 3. dxc5, Black does not try to regain the pawn at once. Instead, 3...d4 pushes the d-pawn forward to claim space and cramp White's queenside development, especially the b1-knight, which loses its natural c3 square. White stays a pawn up, but the extra material consists of doubled c-pawns, and both the c- and d-files are half-open.

4. Nf3 is the usual reply, developing while eyeing the advanced pawn, and 4. e3 challenges the d4 wedge directly. The less common 4. b4 holds on to the c5 pawn and is the engine's first choice; it also scores best for White in practice. The engine gives White a slight edge, yet in online play Black's results are marginally better than White's. The line is an offbeat choice that leads to unbalanced positions rather than to the strategic themes of the classical Queen's Gambit Declined.