Tsukasa Hinoura ‘River Jump’ 165mm Wa-Santoku. Shirogami #2 steel core with 1/2 twist suminagashi iron cladding. Half octagon shaped handle with enju wood and double ferrule water buffalo horn. HRC 63. These are warikomi free forged by hand so measurements and weights can vary slightly. 170mm cutting edge, 49mm high at heel, 312mm overall length 168 grams.
All riverjump knives have different patterns in their suminagashi cladding. The knife in the photo is not the one you might receive.
Hinoura-San’s 'River Jump' is hand-forged with a #2 shirogami, or white steel core, and iron cladding forged with an unusual half twist design. Unlike the usual sandwiched layering of a hon kasumi knife, this series is made with the hagane (cutting layer core) with the iron jigane (cladding) folded around it. These knives are NOT stainless, and extra care should be taken to keep them dry when not in use. The blade will develop a dark patina with use, and any orange rust needs be removed with a light abrasive. Camellia oil is recommended on the blade in between uses.
Tsukasa Hinoura is a third generation knife maker in Sanjo, Niigata, Japan. Hinoura-San uses no modern machinery in the production of his knives, and he does all the finish grinding and sharpening himself. From the forging of the jigane to the final whetstone finish, traditional materials and techniques are employed. Hinoura-San is famous for his heat treatments, coaxing incredible edge life and toughness out of the materials.