comment: An important moment. 6...Bb4 is by far the most popular move.
context: 1. e2e4  1... c7c5  2. g1f3  2... e7e6  3. c2c4 An interesting sideline (if a move with more than ten thousand games can be called that) that is played by very strong GMs from time to time. 3... b8c6  4. d2d4  4... c5d4  5. f3d4  5... g8f6  6. b1c3 