The young Fischer

Once again I am posting before Game 4 of the 2013 World Championship Match has finished. Regardless of the result the talking point is going to be Carlsen's 18th move. Carlsen seemed to be channelling the ghost of Bobby Fischer in deciding to take the a pawn with his bishop (cf Game 1 Spassky Fischer 1972). At first glance it looked like the bishop was trapped after b3, but c4 was enough to save it. As a result Carlsen was a pawn up, although his position is still passive. As I go to print Carlsen is still better (pawn up but defending), but more importantly the momentum seems to be in Carlsens direction. However all three results are on the table, so it is still too early to say if Carlsen's pawn grab is genius or impetuosity.