My old, long-dead-and-buried 1992 Bridgestone RB-1 had Ishiwata tubing. (You should have seen the crack - down tube, seat tube and BB shell all involved. An aluminum or carbon fiber frame would have disintegrated instead of merely getting a tad wobbly.) It had a pretty cool-looking gold decal on the seat tube - it did not look like the one posted above. I have no idea how many model years before or after that Bridgestone used Ishiwata - but I bet Grant Peterson at Rivendell does (he was only their US marketing guru). He also may be able to tell you more about Ishiwata and its provenance. (I seem to remember some marketing material for RB-1's of that era stating something to the effect of Freddy Maertens winning a rainbow jersey on an Ishiwata-tubed frame.)