[%c_effect b6;square;b6;type;Mistake;persistent;true] This move is a theoretical novelty. Far from being preparation, the move is probably the result of So confusing his analysis.
1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. e2e3  4... c7c5  5. g1e2  5... d7d5  6. a2a3  6... b4a5 A fashionable move in the Nimzo-Indian Defense. Historically 6...Bxc3 is more popular. 7. d4c5  7... d5c4  8. c1d2  8... b8d7  9. e2g3 