Yamaju Masuda Shoten 2026: Inside a 130-Year-Old Katsuobushi Workshop in Yaizu Shizuoka

Shizuoka · Yaizu · Craft

A small family workshop in Yaizu still smoking bonito over open fire. Most katsuobushi is now made in large factories.

I went to Yaizu on a weekday morning. The town sits on the Suruga Bay coast, about 15 minutes southwest of Shizuoka by local train. Its port lands more bonito than any other in Japan, and it is one of the country’s main katsuobushi towns. The workshop I came to see is small — a family operation called Yamaju Masuda Shoten, founded in 1887 — and it is one of the very few places left in the country that still makes katsuobushi using tebiyama-zukuri, the original direct-fire smoking method. I wanted to see how the umami in every Japanese kitchen actually gets made. The same family has run it for four generations.

Quick Facts

Why Yaizu, and Why This Workshop

Yaizu has been a fishing port for centuries. The deep waters off Suruga Bay give the city access to skipjack tuna (katsuo) almost year-round, and the local processing industry grew up around that. Many small katsuobushi workshops once ran in Yaizu. Most are gone now — replaced by larger industrial operations or shuttered when the next generation didn’t take over.

Yamaju Masuda Shoten is one of the few left. It was founded in 1887 by Masuda Jugoro and has been continuously operated by the Masuda family since. The business is still small. It uses the smoking method called tebiyama-zukuri — direct fire, no flue gas, kunugi (sawtooth oak) firewood — which most of the industry abandoned because it is slower and more expensive.

The Process, Step by Step

From whole skipjack to finished katsuobushi takes about 25–30 days of smoking for arabushi, plus another seven to eight weeks of mold curing for hongare-bushi. The workshop runs the early stages every working day. Below are the stages in order, based on the workshop’s own description of the process.

Step-by-step

From whole bonito to finished katsuobushi

01

Sorting and cutting. The bonito are frozen fish bought at auction at the Yaizu fish market. They are sorted by size, then headed, gutted and cut into halves while raw.

02

Boiling. The halves are simmered in a large tank at a low boil for about two hours (the time varies with size, freshness and season). This sets the protein and locks in the umami compounds before any smoking begins. The boiling-water vapor is the first cloud you see when you walk in.

03

Splitting and bone removal. After cooling, each half is split again into upper and lower pieces, and the bones are pulled out by hand in water. This is the only stage where the work is slow and quiet.

04

The first smoke. The pieces go onto wooden trays over a direct kunugi-wood fire (tebiyama). The first smoke lasts about 45 minutes; the trays are swapped and smoked for about 40 minutes more. The whole smoking-and-drying stage is called baikan.

05

Cooling, sleeping, repeating. They then move to a multi-level smoke room, where daily smoking (about five hours a day) and resting are repeated for about 25–30 days. With each pass, the loin loses water, the surface darkens, and the umami concentrates inward.

06

Surface trim and inspection. The half-finished loins — at this stage called arabushi — get checked and trimmed. The blackened, hardened surface is cleaned and a small amount of charred wood is scraped away. This is the cheaper grade and the form you’ll find shaved into most everyday dashi packets.

07

Mold curing — four to five rounds. For the fully aged grade — hongare-bushi — the arabushi is moved to a humidity room and a controlled mold is applied. Over weeks, the mold pulls remaining moisture out and develops complex flavor. The mold is brushed off and the pieces are sun-dried, and this mold-and-sun-dry cycle is repeated four to five times over seven to eight weeks. The final product is rock-hard, almost wood-like.

08

Aging and shipping. Finished hongare-bushi goes to restaurants and home cooks who shave it themselves with a wooden plane. Yamaju ships nationwide direct from the workshop.

The Tools

Most of the work runs on hand tools — long filleting knives, pin-bone tweezers, the surface-trim knife with its thick spine. The craftsmen sharpen them every morning.

The smoking area is the largest part of the building. The workshop’s own process report describes eight tebiyama hearths, with wooden trays stacked five high over the fire, and a multi-level smoke room for the later smoking.

Why Tebiyama Matters (For Eaters)

If you cook Japanese food at home, the difference between commodity katsuobushi and tebiyama-style katsuobushi is real and noticeable. The mass-produced flake is smoke-flavored, sometimes lightly. A tebiyama flake has a stronger smoke flavor.

The usual explanation is the fire itself: the fish sits directly over burning wood, with no flue system in between, and is smoked again and again over weeks. The result is a stronger smoky flavor in the dashi.

Once you have shaved a hongare-bushi yourself with a wooden plane and made dashi from it, supermarket pre-shaved flake will taste flat.

How to Visit: The Tour Logistics

Getting to Yaizu

What to Bring

After the Tour: Where to Eat

Yaizu is a fishing town. The katsuo / bonito sashimi served fresh at local restaurants is a local specialty, especially in spring (hatsu-gatsuo) and autumn (modori-gatsuo) seasons. Yaizu Sakana Center, a fish market with sashimi-bowl restaurants, is next to Yaizu IC, about 2 km from the station — take a taxi.

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