1. d2d4  1... g7g6 A fact: nowadays, the decisive games often see some irregular  opening choices. The Pirc/Modern defenses are notorious for that. Some  examples that come to my mind are Ivanchuk-Kramnik, FIDE Candidates'  London 2013 and Karpov-Kortschnoi, Baguio City 1978. 2. g1f3 