Yoo doesn't mind trading the f4-bishop. Other moves avoid this and are very common.
1. d2d4  1... g8f6  2. b1c3  2... d7d5  3. c1f4  3... e7e6  4. c3b5 I must admit that I never quite understood the point of White's game in this opening, with this far-fetched knight-jump. Which is not to say that the variation is bad, as it's played by many strong chess players. 4... b8a6  5. e2e3 The idea is to leave the knight poorly placed on a6, although White loses some time with this and his own knight is no Pegasus. 5... f8e7  6. g1f3  6... e8g8 