My buddy brought over a couple of old frames hoping I could help him get one or both up and running. This was one of them. After we stripped it, I picked it up expecting the heft of a cheap steel frame, but was surprised by how light it was. Magnets and close examination of the welds confirmed that all the tubes except the seat tube were aluminum.

The only clue I have to the identity of this frame is a sticker that reads "Made in Japan for AMF Cycle Division by Bridgestone Cycles Tokyo Japan."

If any of you have big wisdom on what this is, I'd love to learn more about it. Thanks!