There are plenty of sites out there with info on the various White paper and Blue paper steels from Hitachi online.
The compositions can e.g. be seen on this page.
A bit down on the page.
Basically there are 2 White paper steels and three Blue.
White steel seems very popular in Japanese cutlery these days, and imho for good reason.
Properly heat treated they can easily take, and hold a superior edge for quite a long time.
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