Diadrant forks, Bates proprietrary design.
https://www.classiclightweights.co.u...s/bates-cycles
I didn't weight the frame before I built it up, but the frame seemed pretty light and the fork felt heavy. It rides really nice; compliant yet stiff.
There is a theory that Bates (diadrant forks and cantiflex tubes) and Hetchins (curly stays) made distinctively shaped frames so that you could tell what a racer was riding by the silhouette of the frame.