Topalov had used this line as a main anti-Catalan weapon in two WCC matches, against Kramnik and Anand.
1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. g2g3  3... d7d5  4. f1g2  4... d5c4  5. g1f3  5... f8b4  6. c1d2 