Osaka and Edo professional kitchen tradition — developed for kaiseki and high-end vegetable work
The usuba (薄刃, thin blade) is the Japanese professional vegetable knife, ground with a single bevel (kataba) to achieve extreme thinness impossible with double-bevel Western knives. The flat-ground back (ura) creates a slight hollow that prevents suction against cut vegetables. Katsura-muki (rotary peeling) uses the usuba to peel daikon or carrot into a continuous ultra-thin sheet, which is then julienned into needle-thin cuts (ken). This is among the most demanding knife skills in Japanese cuisine — it requires perfect edge geometry, paper-thin blade, and years of practice. The Kanto style usuba has a square tip; Kansai (kamagata) usuba has a curved horn tip.
Technique enables ultra-thin vegetable preparations with clean cut cells, no tearing or bruising
{"Single bevel grind creates thinner, sharper edge than double-bevel possible","Flat ura (back) must be maintained — convex back destroys cutting performance","Katsura-muki: daikon held in left hand, knife moves in rotating peeling motion","Ken julienne: fold the sheet, slice at 1mm or less intervals","Usuba requires frequent honing — single bevel edges roll more easily","Kanto usuba: square tip for precision push-cuts; Kamagata: curved for pull-cuts"}
{"Soak daikon or carrot in water before katsura-muki — hydration makes rotation smoother","Ken julienne standard: 6-7cm length, 1-2mm width — for daikon tsuma in sashimi","Professional test: sheet should be thin enough to read newspaper through","Usuba sharpening: sharpen bevel side on whetstone, then minimal flat-side passes to deburr","Facing cut (katsuramuki substitute): slice thin sheets directly against flat surface for efficiency"}
{"Attempting katsura-muki with a double-bevel or thick knife — physically impossible","Letting the ura become convex through improper sharpening on both sides","Gripping the daikon too tightly during rotary peel — should rotate smoothly","Using twisting motion rather than horizontal cutting motion during katsura-muki","Allowing the knife to angle inward, creating tapering sheets rather than uniform thickness"}
Japanese Cooking: A Simple Art — Shizuo Tsuji; Tokyo Knives — Ikeda Kenji