Strange how lines come in and out of fashion, the variation 1. e4 e5 2. Nf3 d6 3. d4 exd4 4. Nxd4 Nf6 5. Nc3 Be7 having been used by the likes of Joseph Henry Blackburn, Aaron Nimzovitsch and then George Koltanowski. But it was only when Vladimir Antoshin championed it that it gained a measure of respectability.
How should White play against it? I don’t know, but I still like the 6.g3 that I used in the following game as it attempts to inhibit Black’s …d6-d5. I think it got published in some book, though I remember being entirely unconvinced with how I was playing it at the time: