The Suminagashi series feature beautiful Damascus-patterned blades with a core of Blue Paper (Aogami or Aoko) No.1 Steel,
which is "Aoko" or Blue Paper (Aogami) No.1 Steel Knife, made from famous Yasugi steel, known as prime high carbon steel, specifically developed for tools and knives.
This material has highest wear resistance and toughness because of special hardness (hardness of 62-63 HRC). Very good choice for high end Japanese kitchen knives.
The blade is particularly suitable for the gentle preparation of foods though you need to treat the blade to prevent from rust.
Speaking to the precious handle made of "Kurogaki wood" or "Japanese black persimmon", the Octagonal figure fits better comfortably to your hand. In addition, the wood saya sheath (knife cover) is also made of Kurogaki as well.
The Kurogaki is rare and valuable, so the knife series is made for you, high-end customers.
The handle and saya sheath represent special high quality and excellent durability, that means made for professional originally.