[%c_effect a4;square;a4;type;Interesting;persistent;true] A nice move by Fedoseev, and a novelty.
1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. g1f3  4... b4c3 A pretty straightforward approach, but relatively rare. Although, how can the doubling of the pawns can be a rare idea in the Nimzo-Indian $2 5. b2c3  5... d7d6 Building the pawns a'la Capablanca, on the color of the missing bishop, is the quintessence of the line. 6. d1c2  6... d8e7 [#]