1. d2d4  1... d7d5  2. c2c4  2... d5c4  3. e2e4  3... e7e5  4. g1f3  4... f8b4  5. b1c3  5... g8f6 [%c_effect f6;square;f6;type;Interesting;persistent;true] A modern alternative to the more popular 5...exd4. 6. f3e5 