hey, mike: Japanese knives

When I was in one of the large grocery stores in Naha, I saw an exhibition involving a sushi chef cutting up a giant tuna with a giant knife that looked like a sword. What kind of knife was he using? Are they custom-made?

— Billy Chapel

In Japan, there are several different types of traditional edged instruments used in different, sometimes specialized, applications. Knives in general are called hôchô and come in all shapes and sizes. The three most common hôchô used by preparers of sushi and sashimi are the yanagi-bôchô, the deba-bôchô, and the usuba-bôchô. The yanagi-bôchô is used to make thin slices of fish or meat and is often referred to as the sushi knife or sashimi knife in the West. An average, yanagi-hôchô’s blade tends to range from 8 to 12 inches in length. The larger version of the yanagi-bôchô, called the maguro-bôchô (tuna knife) or oroshi-bôchô (preparation knife) can reach lengths of four feet and cost several thousand dollars. The deba-bôchô is a shorter knife used primarily by sushi chefs for cleaning fish. It has a very thick and heavy blade appropriate for chopping off fish heads and tails. Less expensive versions made of stainless steel can be found in the majority of Japanese homes. The usuba-bôchô is often referred to as the vegetable knife. It is used in sushi bars to create paper-thin gari (paper-thin pickled ginger roots used to cleanse the palate) as well as the thread-like strips of daikon often used as a garnish.

Many hôchô, especially those used by sushi chefs, are forged using the same methods as the legendary katana sword—making some of them extremely expensive. Oftentimes, the primary challenge for a smith making an edged instrument is finding the delicate balance between sharpness and durability. Ancient Japanese smiths understood that to attain the best of both worlds, a blade made by welding a durable, low-carbon steel core to a high-carbon steel outer jacket and firing and cooling the two parts “separately” was the answer.

As it is often folded hundreds or thousands of times, the high-carbon steel used for hagane (edge metal) can retain a sharp edge for an extremely long time, but is very brittle. An edged instrument made entirely out of the material would crack or even shatter after only a little use. Low-carbon steel (called shingane, or core metal), on the other hand, has a great deal of “give” and is very durable, but dulls easily and often bends under pressure. However, when carefully melded and augmented with the expert smith’s skill, these component metals become something amazingly sharp and strong.

Today, the creation of a Japanese blade using traditional processes is still regarded as one of the highest forms of metal craft in the world. Whether the blade is a modern-day katana or an expert sushi chef’s blade used to filet a 400-pound yellowfin tuna, the same amount of dedication, precision, reverence, and history are poured into each and every blade—just as it was during the days of the samurai.

—Mike Daley

Got questions for Mike? E-mail editor@okinawa.usmc-mccs.org.