Anglo-Slav Variation, with g3

This position, reached after 1. c4 c6 2. Nf3 d5 3. g3 Nf6 4. Bg2, differs from the parent line in that White has completed the kingside fianchetto without committing to b3. The c-pawn presses on d5 from the flank while the d-pawn stays at home, so White can later choose a double fianchetto with b3 or a central plan with d4. Black's Slav-style pawns on c6 and d5 give a solid center and leave the c8-bishop free to develop.

With Black to move, the most popular reply is 4...Bf5, bringing the bishop outside the pawn chain before ...e6. 4...Bg4 pursues the same goal by pinning the f3-knight. 4...dxc4 changes the character of the game by surrendering the d5-point to win time against the c4-pawn, and 4...e6 keeps the bishop inside the chain, steering toward Agincourt, Catalan or Semi-Slav structures. The engine also favors 4...g6, a symmetrical fianchetto. It assesses the position as roughly balanced, and White scores slightly better than Black in practice.