That's a bit general for yasuki steels, though. There are at least three classes of white, with the numbers given in that summary lining up with the top subclass of white #2 and blue #2.
I've used blue 1, blue 2, white 1 and white 2 (never saw white or blue 3), blue and white 2 are very common in hand tools. There are also specializations of the steels beyond just the white and blue (some of the tool makers get specialty lots and share them)
But specifically what I'm curious about is what is ysk2, is it white #2 (it doesn't seem like it) or blue #2? (maybe) or is it something specialty that is more highly alloyed (that also seems like a possibility).