I recently obtained some additional details on these steel products from
the manufacturer, Hitachi Metals. I inquired, hoping to purchase some for
making tools. Shinichiro Kitagawa of the San Jose office was kind enough
to provide me with a quote for the grades in which I am interested.
Unfortunately, the minimum order quantity for shipment to the US is 500
lbs per grade, so I won't be able to make a purchase right away...
By the way, my receiving a quote for these materials refutes the
occasionally stated claim that certain grades of these products are sold
only to toolmakers who meet specific skill requirements imposed by
Hitachi. The only thing Hitachi required of me to become a customer was
Here's the scoop:
The facilities at Hitachi's Yasugi Works produce a number of steel and
other metal products. They are sometimes identified as "Yasuki" (because
they're made at the Yasugi plant) or "YSS". The steel stock used by
Japanese woodworking edge tool makers is called "YSS High Class Cutlery"
steel and is wrapped in paper or labeled by the manufacturer. The color
of the paper or label indicates the type of steel.
I think there may be a play on words in the names, as "gami" means "high
class," but "xx-gami" usually refers to a type of paper ("xx-" being the
type). For examples, "atsugami" is cardboard or thick paper, "hanagami"
is tissue paper, "gingami" is silver paper, and so on. However, I don't
speak Japanese, and would appreciate input on this from anyone who does.
Incidentally, I also have a brochure for these steels in Japanese (it's
not available in English). If anyone can help translate it for me, I
would be indebted.
White steel is a common shorthand name for white paper steel ("shirogami
hagane") which can be any of several fairly simple high carbon, water
hardening steel grades. The carbon content varies by grade, and runs from
0.8 to 1.4%. The range of carbon content within a grade is a tight 0.1%.
For example, the carbon content of Shirogami Hagani No1A is specified to
be between 1.3 and 1.4%. Each grade also contains 0.1-0.2% silicon and
0.2-0.3% manganese, and only trace amounts of the impurities sulfur and
Blue paper steel ("aogami hagane") is also offered in several grades,
with carbon content ranging similarly to the "white" grades. However,
blue steel contains the additional alloying elements chromium and
tungsten, and one grade ("aogami super") also contains molybdenum and
vanadium. The blue steels can be quenched in water or oil, whereas most
of the white grades need a faster quench and require water.
A list of the YSS high-class cutlery steel grades and the specifications
for their composition, heat treatment and hardness is available on my web
Thanks to Hitachi Metals, Ltd, for the information.