Fuji had some very good steel alloy bikes made in the 1970s and early 1980s whose tube sets were made by Ishiwata. You can identify some by the decals. Some can be identified by "Ishwata" being stamped on the steering tube. Ishiwata is every bit as good as Columbus and Reynold 531 of teh same period. Tange made some good stuff, too, but, I would put my money on an Ishiwata frame, then, go from there.