1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. g1f3  3... f8b4  4. c1d2  4... c7c5 [%c_effect c5;square;c5;type;Interesting;persistent;true] This is an interesting variation of the Bogo-Indian Defense, a favorite of the legendary GM Viktor Korchnoi. I played this move many times during my career, but I must admit that my results were not as good as Korchnoi's and Nakamura's, which is not so surprising, to be honest.