Hakata Kurouchi 165 mm (6.5 in)Type: Hakata Finish: Kurouchi Blade Length: 165 mm (6. 5 in) Construction: Awase Core Edge Steel: Aogami (Blue) #2 HRC (Rockwell Hardness): 60 61 Handle: Walnut Octagonal Resin Ferrule Bevel: Double Bevel Place of Origin: Tosa, Japan Blue (Aogami) #2 (Hitachi Metals Ltd.) is made by adding Chromium and Tungsten Wolfram to White Steel #2. This results in increased toughness and the production of hard carbide molecules, which improve edge retention.