1. e2e4  1... e7e5  2. f1c4  2... g8f6  3. d2d3  3... b8c6  4. b1c3 Nepomniachtchi has been extremely  successful in reviving this old Vienna line. 4... f8b4 This should not  have come as a surprise for Nepomniachtchi as Giri used the line twice  recently to hold on against strong opposition. 5. g1f3  5... d7d6  6. e1g1 