Named for blue paper put on steel at Hitachi factory. Aogami (blue) steels are graded as Super, #1 and #2.. All made from same iron stock as Shirogami (white) steel, Aogami steels have high carbon (1.1-1.5%), .5% chromium for carbide formation and tungsten for edge life.
Aogami steels do not sharpen as easily as Shirogami but they cut better as they dull. Typically, Aogami 1 has the best edge formation of the Aogami family.
Highly recommended for professionals that need good edge life and can sharpen as needed. Aogami steels have little corrosion resistance and special attention is required to prevent rusting.