You'll have to talk more on the history of this era of Rocky as interested to know and where in Japan they where built, etc.. 5lb+ frame ?
I'm fairly certain that these Japanese Rockys came from Toyo, same as many Bridgestones and Yokotas and many others. Toyo built a bunch of stuff for folks back in the day, and they still build for folks like Rivendell. Toyo built frames are quite the secret in the MTB world, as they don't fetch a bunch of dough, but Toyo (and similarly, Panasonic built frames) are very well constructed. The welds on my Yokota are some of the prettiest I've seen, and most folks have no idea what the hell that frame is!
I'm not 100% sure that the frame is from Toyo, but that's my understanding. I'm sure some of the usuall suspects in the Rocky Mountain brain trust on Retrobike can chime in with more info. I'd be interested to know more too. I have to admit... I wanted the Yokota because ist was a Toyo, but the Rocky...well, I wanted that because its a Rocky!
Come to think of it...I think my '89 GT Avalanche is a Toyo frame too. I may have an accidental addiction of sorts going on here!
Weight for the Rocky? I've no idea. Lets just say, more than my Klein, but less than the EWRs!
Drowning in Retro!