Koyanagi 135 mm (5.3 in) Blue#2Type: Koyanagi Finish: Kurouchi Damascus Blade Length: 135 mm (5. 3 in) Construction: Awase Core Edge Steel: Blue (Aogami) #2 HRC (Rockwell Hardness): 61 63 Handle: Rosewood Octagonal 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. Many