The Classical Variation, Berlin Variation, Macieja System is a variation of the Nimzo-Indian Defense, catalogued as ECO E39. The line runs 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 c5 5. dxc5 O-O 6. a3 Bxc5 7. Nf3 b6, reaching the position shown below after 14 half-moves.
The four central squares are empty of pawns, so the fight for them is being conducted by pieces. Development is level at two minor pieces each. It is White to move after seven moves. Black has castled while White’s king is still uncommitted.
On the Nimzo-Indian Defense generally: One of the most respected defenses to 1.d4. Black pins the knight and fights for central control.
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The Classical Variation, Berlin Variation, Macieja System goes 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 c5 5. dxc5 O-O 6. a3 Bxc5 7. Nf3 b6. It is a variation of the Nimzo-Indian Defense and is catalogued as ECO E39.
The Classical Variation, Berlin Variation, Macieja System is ECO E39. ECO codes group openings by their move order, so nearby codes cover closely related lines of the Nimzo-Indian Defense.
Stockfish evaluates the position after 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 c5 5. dxc5 O-O 6. a3 Bxc5 7. Nf3 b6 at +0.37 at depth 18, which is a slight pull for White, within normal opening margins. Engine evaluation is only a starting point — at club level the practical value of a line is mostly about whether you know its plans better than your opponent does.
The four central squares are empty of pawns, so the fight for them is being conducted by pieces. Development is level at two minor pieces each. It is White to move. Black has castled while White’s king is still uncommitted.