1. e2e4  1... c7c6  2. d2d4  2... d7d5  3. e4d5  3... c6d5  4. f1d3 The Exchange line that Fischer revived in the 1970s lives a new life thanks to the rise of the London System. A lot of positions transpose from both the openings and the pawn chains are quite similar. 4... g8f6  5. h2h3 Underlining Black's major problem in the position: the future of his light-squared bishop. 5... b8c6 