Modern Defense: what to play after Bc4?

In this branch of the Modern Defense, Black faces White's early bishop development to c4. Engine evaluation narrowly favors c5 (+0.23), which immediately challenges White's central space, though the overwhelming human choice is the traditional fianchetto with Bg7 (+0.25). Both moves offer Black solid central counterplay with almost identical scoring outcomes for White.

The immediate strike with c5

Although c5 represents only 0.4% of games in the database (43K recorded), it provides an effective way to challenge White's control over the center. White scores 49.8% from this tabiya, illustrating balanced play. An illustrative continuation demonstrating Black's thematic counter-strike runs c5 c3 Bg7 d4 cxd4 cxd4, where Black exchanges the c-pawn to dismantle White's initial pawn center while setting up the bishop on g7.

The standard development via Bg7

By far the most common continuation is Bg7, occurring in 91.6% of games (8.95M recorded). Black simply follows standard Modern Defense principles by completing the kingside fianchetto to exert diagonal pressure toward the center. White scores 49.3% in this continuation, and the top engine sequence shows transpositions into similar structures: Bg7 d4 c5 c3 cxd4 cxd4.

Alternative continuations

Black possesses several functional alternatives that feature slightly higher evaluations for White. The flexible pawn move d6 appears in 3.2% of games (308K recorded) with an evaluation of +0.39, where White scores 51.7% following d6 d4 Nf6 Qe2 Nc6 Nf3. The French-like advance e6 is chosen in 4.4% of games (428K recorded, +0.56 eval), prompting queenside expansion via e6 Nc3 a6 d4 b5 Bd3. Finally, Nc6 accounts for 0.4% of recorded games (44K recorded, +0.60 eval), leading into Nc6 d4 d6 Nc3 Nf6 f4, where White scores 52.0%.