Chess Opening Theory/1. d4/1...Nf6/2. c4/2...e6/3. Nc3/3...Bb4/4. e3

Nimzo-Indian Defence rd nd bd qd kd rd pd pd pd pd pd pd pd pd nd bd pl pl nl pl pl pl pl pl pl rl bl ql kl bl nl rl Nimzo-Indian Defence, Rubinstein Variation 4. e3 White assesses that an immediate 4...Bxc3 is not a threat, but also that 4. a3, provoking the capture, is not necessary (yet). Instead, 4. e3 simply clears the way for White's light-squared bishop to develop, usually to d3, where it helps control the all-important e4 square. Black has three main responses: 4...O-O is the most common. Since Black will never castle queenside in a Nimzo-Indian, castling kingside now is a useful but still highly flexible move. 4...c5 puts pressure on White's center immediately. Taking on c5 and accepting tripled isolated pawns (after ...Bxc3 bxc3) is right out of the question, and pushing d5 now simply creates a target, so White instead continues his development and leaves the tension. 4...b6 is the St. Petersburg Variation (not to be confused with the Leningrad Variation). This move prepares to strengthen Black's control of e4 yet further by fianchettoing a bishop to b7, though ...Ba6 is not yet out of the question. In all three cases White has a choice between 5. Nge2 and 5. Bd3. Theory table . 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 4 5 6 7 Rubinstein System ...O-O Bd3d5 Nf3c5 O-Odxc4 = ...c5 Ne2cxd4 exd4O-O a3Be7 = Hübner Variation ...... Bd3Nc6 Nf3Bxc3 bxc3d6 = St. Petersburg Variation ...b6 Bd3Bb7 Nf3O-O O-Od5 = Fischer Variation ...... Nge2Ba6 a3Bxc3 Nxc3d5 = ...... ...Bb7 a3Be7 = Nimzo-Indian Defence