A difficult decision.
1. d2d4 Robson is a great attacking player; his best games feature accurate handling of the initiative and excellent calculation. The natural move for a player with this style is 1.e4, where he has great games, but it's interesting to see how he manages to direct the game toward a dynamic opening also with the queen pawn. 1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. e2e3 The most classic variation against the Nimzo-Indian, a line of extraordinary strategical complexity. 4... e8g8  5. f1d3  5... c7c5  6. g1e2  6... d7d5  7. c4d5  7... c5d4  8. e3d4  8... f6d5  9. a2a3  9... b4a5 It's not clear which square is best for the bishop, as all three are possible. 10. e1g1  10... b8c6  11. d3c2 Starting the traditional plan with the battery of queen and bishop pointing to the kingside, so common in positions with an isolated queen's pawn. 11... a5c7  12. d1d3  12... d8h4 Defending the mate on h7 and threatening mate on h2 at the same time. 13. h2h3 This natural move is new, which shows that there's still a lot to be explored in this opening. 13... d5f6 This move is probably not the most accurate, as the black queen is in an uncomfortable situation on h4. 14. c1e3  14... f8d8  15. d3d2 [%c_effect d2;square;d2;type;GreatFind;persistent;true] A clever plan, forcing Black to play h6. 15... h7h6 Otherwise, White plays 16.Bg5. 16. f2f4 [%c_effect f4;square;f4;type;GreatFind;persistent;true] now White combines the advance on the kingside pawns with an attack on Black's vulnerable queen. Robson has the kind of position he likes, but of course, Black still has a lot of resources. 16... f6d5  17. e3f2  17... h4f6  18. a1d1 