Lesson
White to move. Main line: 1. d4 Nf6 2. Bg5 Ne4 3. Bf4 d5 4. e3 c5 5. Bd3 Nc6 6. Bxe4 dxe4
The Trompowsky avoids many Indian-defense move orders by developing the c1-bishop before White plays c4. Black’s 2...Ne4 is active: the knight occupies the square the bishop was indirectly contesting and invites White to define the position.
White retreats to f4, develops the other bishop and eventually exchanges it for the centralized knight. Black recaptures with the d-pawn, gaining space on e4 but accepting a pawn that can become a target after Nc3 and f3.
The opening is not just an early pin. White must decide whether to exchange on f6, retreat, or challenge the e4-knight; Black must decide whether central space compensates for structural commitments. Those decisions begin on move two.