Semi-Slav Defense: what should Black play?

In this classic tabiya of the Semi-Slav Defense, Black's most accurate theoretical choice according to engine analysis is h6, which carries an evaluation of +0.23. This flexible probe challenges the active g5 before committing the black king or queen's knight. While h6 is favored by engines, Black also frequently chooses between Nbd7 and O-O to maintain solid piece coordination.

Probing the Bishop with h6

Chosen in 18.5% of recorded games (834K recorded), h6 immediately forces White's dark-squared bishop to clarify its intentions along the diagonal. In the primary illustrative continuation h6 Bf4 Nbd7 Qc2 Nh5 Be5, White retreats the bishop to f4, after which Black initiates piece maneuvers against White's minor pieces while keeping White to an overall scoring rate of 55.6%.

Alternative Development Schemes

Black's most popular practical choice is O-O, occurring in 45.8% of games (2.07M recorded) with a +0.32 engine evaluation and a 54.5% White score. An illustrative line runs O-O Qc2 Nbd7 h4 a5 a3. Meanwhile, Nbd7 represents 29.9% of games (1.35M recorded), holding a close +0.25 evaluation where White scores 54.2%, demonstrated in the continuation Nbd7 Qc2 h6 Bh4 O-O a3.

Offbeat Approaches

A sharper, less common pathway is Ne4, played in 5.6% of games (253K recorded) with an evaluation of +0.39, leading to the line Ne4 Bf4 Nd7 Qc2 Nxc3 bxc3 where White scores 51.7%. The flank advance a5 remains rare at 0.2% of games (10K recorded) and +0.44, illustrated by a5 Bd3 O-O O-O Nbd7 Rc1 where White scores 55.5%.