I wouldn't be surprised if they weren't the only ones to use it. But if you don't tell anyone what you are using, tough to know if someone else is using the same thing. Especially with different heat treats, cladding, etc.
Iwasaki (and whoever is working for/with him), Shigefusa (et al) and Heiji (et al) all use the same steel, most likely with the same HT. How many people is that? Sounds like a crowd to me. It's probalby a combiniation of a well kept secret and that there probably just aren't a whole lot of people that care.
The steel came in today. The chemical cert says that it has 1.27% C, .007 P, .001 S with a few other standard elements and a very small amount of grain refining alloy.
It is some of the cleanest steel I've ever seen.
I'll laminate some this week I hope. (sanmai with 403 stainless on the out side)
SWEET. I can't wait to see what you think of it.
yup! can't wait