Opening up an old thread because I have come across more information via a the same razor recently sold on Etsy/shavearmory's website. He calls it a
Inoue Tosuke Kikusui Steel Kamisori
This is a gorgeous example of one of the highest quality Inoue Tosuke blades ever produced. This is due to the fact that it is made of a solid piece of high purity and fine grain structure Kikusui steel. This steel allows for a very fine edge that will hold its sharpness longer than other steels. Since Kikusui steel has not been produced for many years, these are very special and rare vintage blades. These razors have been decoratively boxed to signify their exceptional quality.
I also have a stainless Tosuke with the same gold stamp and a similar decorative box. And it is nice to know that it is made from a solid piece of high purity and fine grain structure Kikusui steel. Thanks for that. And my factory new Iwasaki kamisori is one-piece Swedish stainless. So yes, they do make stainless kamisoris.