Hansen: The Nimzo Indian 4.e3Comprehensive coverage of the long established main line of the Nimzo The reprint of the 2002 classic! Ever since Nimzowitsch introduced his flexible, dynamic defence to the queen's pawn, debate has raged over White's best reply. Many variations have been in and out of fashion, but one line in particular has proved an enduring weapon the sound and solid 4 e3 line, known as the Rubinstein Variation. The 4 e3 Nimzo is extraordinarily rich in strategy.