TAMAYUKI is variety of TAMAKONGOU and produce tiny stirpe. Variegated Tamakongou is very popular and many of Fukiran growers including my father have seen so many mutation from Tamakougou with little bit stripe on them. Hakujitsumu, TENSEI, KONGOUHOU (these super high end variegated bean leaf now days) all came from Tamakongou with little stripe.
There are so many stories my father shared with me how Tamakongou mutated and produced amazing stripe or marginal stripe after he sold them to hobbyist. Interesting part is they never mutate in our greenhouse, always after they left us lol.