[%c_effect a6;square;a6;type;Inaccuracy;persistent;true] This is too slow, and White gets a comfortable advantage.
1. d2d4  1... g8f6  2. c2c4  2... g7g6  3. b1c3  3... f8g7  4. e2e4  4... e8g8  5. f1e2  5... c7c5  6. d4d5  6... d7d6  7. h2h3  7... e7e6  8. g1f3 