Spassky System

The Spassky System, 4. e3, is a modest reply to the Queen's Indian. White passes up the fight for the long diagonal with g3 and does not prepare e4 with a3. Instead the pawn on e3 supports d4, frees the king's bishop for Bd3 and allows quick kingside castling, at the cost of shutting in the queen's bishop. White's c4-d4-e3 chain gives a compact center, and the game often stays positional, with play around the e4 square and possible breaks such as ...c5 or ...d5 for Black.

Black usually develops with 4...Bb7, chosen in the large majority of games, aiming the bishop at e4. After 4...Bb7 5. Nc3 Bb4 the game can pass into the Nimzo-Indian. Less common are the check 4...Bb4+ and 4...Ba6, which hits c4 but has scored poorly for Black in the database. The engine also rates 4...d5 among the best replies and regards the position as roughly balanced. Overall results are almost even, and the line sees moderate use.