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The Portuguese: 4.f3 Bf5 5.g4

With 2…Nf6 3.d4 Bg4 4.f3 Bf5, you score 88% against 5.c4, but 33% against 5.g4. The same position, two different worlds.

Recall: after 5.Bc4 Bg4 6.f3 Bd7 7.Ne2, which pawn move?