i think blue 2 is just white 2 with added tungsten and chromium. which in theory should produce less reactivity and alittle better retention. in turn you sacrifice ease of sharpening and maybe some toughness?
according Hitachi Steel Co. information, "JIS SK steel">purify>"yellow#2">purify>"white#2">purify & added C, Cr>blue#2
Charles ***[All statements I made here only my personal opinion and nothing more!]*** & Please bare with me for my crappy English!!
maybe it was just the heat treat or something else, but actually the difference to me besides retention was that blue steel seems at its best with a 2-4k toothy finish while white seems to really shine with a 6-8 finish.
This is new to me. I am going to try it out and see.