Chef's Knife : Sushi Edition|Tokyo Sushi School - Become a Sushi Chef in Just One Month

Why Knives Matter in Sushi

In Japanese cuisine-and especially in sushi-knives are absolutely essential. Unlike the all-purpose kitchen knives found in most homes, sushi chefs use traditional Japanese knives, known as wa-bōchō.
Before we talk about those, let's first look at the knife most families know well: the santoku-bōchō.

The Santoku: A Knife for Every Household

The santoku, which means "three virtues," was born in Japan during the Meiji era, when beef began to be eaten and Western-style knives were introduced.
At that time, Japanese households mainly used the nakiri-bōchō (a single-edged, rectangular knife for vegetables) and the deba-bōchō (a heavy knife for filleting fish). When Western carving knives arrived, Japanese craftsmen adapted the shapes to create a versatile knife that could handle vegetables, meat, and fish. This became the santoku-a Japanese-made, double-edged knife influenced by Western design, and still a staple in homes today.

Japanese Knives for Professionals

Professional sushi chefs, however, rely on single-edged knives (kataba-bōchō). Unlike double-edged knives that "cut through," single-edged knives "slice away," producing incredibly sharp cuts with minimal resistance.
Think of the long, slender yanagi-ba sashimi knife: instead of pressing down, the chef pulls the blade smoothly toward themselves. The result is a perfectly clean cut that does not damage the delicate cells of the fish. This preserves texture, shine, flavor, and even freshness.
That is why traditional Japanese cuisine relies on a set of specialized knives: the deba for filleting fish, the yanagi-ba for sashimi, and the usuba for fine vegetable work such as peeling daikon into paper-thin sheets.

The Steel Behind the Blade

Japanese knives are typically made from three materials: stainless steel, ceramic, and high-carbon steel (hagane). While stainless is common in households for its easy care, professionals prefer carbon steel for its unmatched sharpness.
Carbon steel is an alloy of iron and carbon-the same material used for Japanese swords. By adjusting the amount of carbon and adding other elements like chromium or tungsten, craftsmen produce steels of different hardness levels. Harder steels keep a sharp edge longer but are more difficult to sharpen. Softer steels are easier to maintain but dull more quickly.
This is why Japanese knives can be expensive: the steel itself, the forging techniques, and the balance between sharpness and workability all add to their value. Just as a world-class violinist invests in a fine instrument, a sushi chef must invest in high-quality knives.

Knives, Whetstones, and Daily Care

For a sushi chef, fresh ingredients and sharp knives are equally important. Even the finest fish cannot become excellent sushi without a well-maintained blade. Daily sharpening on whetstones is part of the chef's routine.
Different sizes of deba are used depending on the fish: large ones for sea bream, small ones for horse mackerel or kohada. Whetstones also vary-rough stones for repairing chips, medium stones for everyday sharpening, and fine finishing stones for polishing the edge.
For anyone aspiring to become an Edomae sushi chef, the journey begins not only with fish and rice, but with good knives and proper sharpening stones. Many students start by visiting Tokyo's Kappabashi district, famous for culinary tools. Investing in the right equipment at the beginning is the first step toward mastering the craft of sushi.

Sushi and the Japanese Chef's Knife