Vol. XXVIII · The Cuisine of Japan Plate 4 of 11Japanese knives, 和包丁, single bevel, 片刃, usuba, 薄刃, deba, 出刃, yanagiba, 柳刃, gyuto, santoku, katsuramuki, 桂剥き, rotary peel, daikon, ken, つま, pull cut, sashimi slicingTM

Japanese Knives and Cuts.

A trainee peels a 7 cm daikon into a single sheet a few metres long and thin enough to read through. The geometry says exactly how long.

A Western knife is ground on both sides (double bevel); a traditional Japanese knife (和包丁) is ground on one side, the front, and is flat or slightly hollow on the back (IV.1). For the same edge angle the single bevel is thinner and makes a cleaner cut, and the flat back lets the cook take very thin, even slices — but the knife steers slightly towards the flat side, and it must be used right- or left-handed. The three classic shapes are the usuba (薄刃), a thin rectangular vegetable knife; the deba (出刃), thick and heavy, for heading and filleting fish through bone; and the yanagiba (柳刃), long and slender, for sashimi. Modern Japanese cooks also use the double-bevelled gyūtō and santoku (IV.8).

The cuts follow the knives. Sashimi is sliced with a yanagiba in a single long pull from heel to tip, never sawing, so the surface stays smooth and glossy (hira-zukuri 平造り, thicker; usu-zukuri 薄造り, paper-thin for firm fish). The usuba's great exercise is katsuramuki (桂剥き): a length of daikon turned against the blade so that the knife peels it into one long continuous sheet, which can then be stacked and cut into fine threads (ken, けん) to garnish sashimi. Its length is pure geometry: the volume of the daikon removed, spread into a sheet. The workshop peels a daikon.

Below: the length of the continuous sheet when a daikon of the diameter you choose is peeled with katsuramuki down to the core you choose, at the sheet thickness you choose (exact geometry: area of the ring ÷ thickness), with the cross-section of the daikon.

What you will learn
Workshop
Exact geometry: sheet length = π (R² − r²) ÷ t for a daikon of radius R peeled to a core of radius r at sheet thickness t (all in mm), assuming even thickness. Practice targets (common in Japanese training): about 0.5 mm, thin enough to see light through.

One long sheet, one long pull

A daikon 70 mm across peeled down to a 25 mm core gives a sheet about 3.4 m long at 1 mm, 6.7 m at 0.5 mm and 13.4 m at a masterly 0.25 mm. Every halving of the thickness doubles the length — and the difficulty, since the sheet must not tear. Trainees practise on short lengths of daikon or cucumber, holding the vegetable in the left hand and turning it into a still blade, the right thumb guiding the edge.

For sashimi, chill the fish, wipe the yanagiba, and set the heel of the blade on the far side of the block; draw the whole length of the knife towards you in one stroke, letting its weight do the work, and lay each slice to the right, leaning on the last. A single-bevel knife is sharpened mostly on the front bevel, with a few light strokes flat on the back to remove the burr (IV.6). Keep Japanese carbon-steel knives dry, wipe them between cuts, and never use them on bone or frozen food unless they are made for it, like the deba.

At the stove

Practise katsuramuki on a 10 cm length of cucumber or daikon. Measure your sheet and work out its average thickness from its length.

Sakai, near Osaka, has made knives since the sixteenth century, when its smiths turned from swords to tobacco knives; it still produces most of the professional single-bevel knives used in Japanese kitchens, with forging, grinding and handle-fitting done by separate craftsmen.

Terms

Single bevel (片刃)
Edge ground on one side only, flat at the back.
Usuba / deba / yanagiba
Vegetable / fish-butchering / sashimi knives.
Katsuramuki
Peeling a vegetable into one continuous thin sheet.
Pull cut
Slicing in one long stroke towards the cook.
Japanese knives are often single-bevelled: thinner, more precise, made for one hand. Usuba for vegetables, deba for fish bones, yanagiba for sashimi in one long pull. Katsuramuki length = π(R² − r²) ÷ t: a 70 mm daikon gives about 7 m at 0.5 mm.

Sources

  1. S. Tsuji, Japanese Cooking: A Simple Art, Kodansha, 1980 (rev. 2006).
  2. A teaching value chosen for the course: the right order of magnitude and shape, not a measurement of a particular food.