I am staring in disbelief at a diagram in the Purdy Project article. The diagram in my magazine shows Black being a queen down. There is no way I am buying that 27. Bf3 is even needed in this position. I would just take the rook on e3 and try not to laugh…
Now if there is a black queen perhaps on b8, c7, or d6 this would restore the material balance and help clarify why 26.Re3 was played. And then Bf3 becomes a quite profound defense.