Our handmade Yoshihiro Blue Steel Suminagashi knives are crafted with extraordinary skill by our master artisans. Exemplifying the most intricate techniques of forging, layering, and hammering, Aoko Blue Steel 1 with a hardness on the Rockwell scale of 64, is forged with iron to create the most elaborate of finishes. Suminagashi translates as floating ink and refers to the beautiful marbled wave like patterns that extend through the blade from the tip to the heel, unveiling a new mosaic with every sharpening. Only the most skilled of artisans can forge together these metals in such complex puzzle piece formations to fashion knives of this caliber with the highest quality, blending aesthetics and performance. Our Yoshihiro Blue Steel 1 Suminagashi knives are complimented with a traditional Japanese style handcrafted premium Ebony wood handle of the highest quality affixed with a Water Buffalo horn bolster, and a protective wooden sheath called a Saya is included, which protects the knife and adds to its appearance when not in use. The Kiritsuke knife is a traditional Japanese all purpose chefs knife that resembles a sword. Its length allows it to cut sushi and sashimi like a Yanagi, and the wideness of the blade gives it the dexterity to do multiple jobs. The sword tip also helps balance the weight of the knife and can be used for intricate and precise knife work for exquisite service. Even the simplest of tasks are elevated with a handcrafted knife that is as beautiful as it is functional. Although traditional Japanese carbon steel knives are not stainless, with proper care they can provide years of enjoyment. Keeping dry in between usage, and applying Tsubaki Oil(as included) before storage will keep your knife in tip top shape. Japanese knives should always be sharpened and honed on premium quality Japanese water stones.