Modern Defense

The Modern Defense, classified under A40, meets 1. d4 with 1...g6, which prepares ...Bg7 and leaves the central pawns unmoved. Black gives White the center for now and gets quick kingside development in return, with the bishop aimed down the long diagonal at d4. Because Black has committed to so little, the move is mainly a transpositional device. If White replies 2. e4, the game becomes the Modern Defense proper (also called the Robatsch) or, once Black adds ...d6 and ...Nf6, the Pirc. Many 1. d4 players prefer to stay in queen's pawn territory.

The typical structure is hypermodern. White builds a broad center, and Black uses the fianchettoed bishop together with later pawn and piece pressure to undermine it. Black's choice about the d-pawn and the king's knight decides which structure follows. With ...Nf6 the game usually reaches Indian Defense territory. With ...d6 and the knight held back, Black keeps Modern-style flexibility and can delay the decision about the e- and c-pawns.

On Lichess, 2. c4 is the most frequent reply by a clear margin. After 2. c4, 2...Nf6 transposes to the King's Indian Defense, and 2...d6 is a further option. 2...Bg7 invites 3. Nc3 or 3. e4, and both often lead to the Averbakh System of the Modern Defense, where White has pawns on c4, d4 and e4. 3. Nf3 is also playable and frequently transposes into another line.

The quieter 2. Nf3 and 2. Bf4 follow, each played in roughly a sixth of games. They keep White's options open and allow setups such as the London System, while Black can still choose between Indian and Modern formations. Engines favor the direct 2. e4, followed by 2. Nc3 and 2. Nf3, and give White a slight edge after 1...g6.

The position is among the more frequently reached named openings in the database. White and Black score almost equally in practice, and very few games are drawn. Play tends to be maneuvering and strongly shaped by transpositions, so a player choosing 1...g6 needs to know the King's Indian and Pirc structures it can lead to.