Nimzo-Indian Defense, Leningrad Variation

The Leningrad Variation is defined by moving White's bishop from c1 to g5, written Bg5 in algebraic notation. The idea is to develop the bishop before advancing the e-pawn to e3, because that pawn would reduce its natural diagonal. From g5, the bishop attacks Black's knight on f6 and influences the fight for the center.

White must still address the pin on the c3-knight, meaning the pressure from Black's bishop on b4 that prevents the knight from moving without exposing the king. Black can attack the g5-bishop with h6, strike the center with the c- or d-pawn, or exchange on c3. The bishop's value depends on whether it keeps an active square without losing several moves.

The line creates concrete decisions before a fixed structure. Compared with the Romanishin Variation, which prepares the king's bishop for g2, the Leningrad develops the other bishop first.