1. d2d4  1... g8f6  2. g1f3  2... b7b6  3. c2c4  3... c8b7  4. b1c3  4... e7e6  5. g2g3 This offers Black a choice  between the Queen's Indian and the Nimzo-Indian defenses. 5... f8b4  Kovalenko chooses the latter. 6. f1g2  6... b4c3  7. b2c3 