How Japanese Dried Bonito Is Made

This workshop founded in 1882 still makes dried bonito like they did back in the Edo period.

How katsuobushi — Japanese dried bonito, said to be the world’s hardest food — is made in Nishi-Izu, Japan. Inside Kanesa Katsuobushi Shoten, a workshop founded in 1882, 5th-generation craftsman Yasuhisa Serizawa still uses the 200-year-old “tebiyama” hand-fired smoke-drying method that only a few workshops in Japan preserve. Watch fresh bonito being filleted and boiled for 90 minutes, smoke-dried more than 10 times over a hand-tended wood fire, repaired with bonito paste, fermented with koji mold and sun-dried for months — over half a year until the fish becomes as hard as wood and shines like a jewel. From fresh catch to katsuobushi.

Check out Kanesa Katsuobushi Shoten’s website for more info; here’s what they say about the tebiyama drying/smoking method (Google translation):

This method of making dried bonito flakes has been used in the Tago district of West Izu for a long time, and its history is said to date back about 300 years (to the Edo period). It involves digging a vertical hole about 2 meters deep, burning firewood (raw wood from Izu: oak, sawtooth oak, cherry, etc.) from the bottom of the hole, and smoking and drying the dried bonito flakes with the high temperature of an open flame. This method is called the Tebiyama-shiki smoking method. It is the oldest existing smoking method, and only a few bonito flake manufacturers in the country continue to use this method to make dried bonito flakes, so it is said to be a legendary method. The Tebiyama-shiki smoking method is said to produce dried bonito flakes with a rich flavor because the surface of the bonito is smoked all at once with the high temperature of an open flame, locking in the umami.