Established Soy Sauce Brewery Since 1688, Preserving the 1% 'Wooden Tub Culture' for the Future – Public Unveiling of Wooden Tub Replacement with Coopers (April 16th - 10 Days) Media and Photography Welcome

Shibanuma Soy Sauce Brewery Co., Ltd. (Head Office: Tsuchiura City, Ibaraki Prefecture, Representative Director: Hidetoshi Shibanuma), with over 330 years of history since its founding in 1688 (Genroku 1), will be replacing its wooden brewing vats (renewal) for approximately 10 days starting from April 16, 2026.

This initiative is part of an effort to pass down the culture of "wooden tub brewing," which accounts for only about 1% of domestic production, to the next generation.

Furthermore, this process is open for media coverage and photography, allowing direct observation of the wooden tub craftsmanship.

Wooden Tub Brewing: A Rare Method Accounting for 1% of Domestic Production

Currently, most soy sauce in Japan is produced in stainless steel tanks.

In contrast, wooden tub brewing accounts for only about 1% of the national production, making it an extremely rare method.

While wooden tubs can be used for over 150 years, their numbers have been declining due to reasons such as:

・Labor-intensive

・Low production efficiency

・Difficult management

The Crisis of Wooden Tub Culture – Only a Few Coopers Remain

Even more serious is the decline in the number of coopers who can manufacture wooden tubs.

Around 2010, there was only one cooperage company nationwide, and currently, the number of individuals carrying on this craft is limited to a few.

If this trend continues, it may become impossible to maintain wooden tubs themselves.

"Wooden Tub Renewal" Conducted with Coopers

In this initiative, existing wooden tubs will be removed and replaced with new ones (four tubs). The work will be carried out over approximately 10 days with the participation of Mr. Takeshi Ueshiba, a cooper from Osaka.

Wooden tubs cannot be mass-produced by machines; each one is meticulously assembled by the skill of a craftsman.

Industry-Wide Initiative: "Wooden Tub Cooper Revival Project"

Shibanuma Soy Sauce is also participating in the "Wooden Tub Cooper Revival Project." This project involves collaboration between breweries of soy sauce, miso, sake, and coopers, who gather annually on Shodoshima Island to build new tubs.

Under the philosophy of "not competing for the 1%, but making the 1% into 2%," the project aims to pass on the wooden tub culture.

Shibanuma Soy Sauce participates in and supports this project through regular orders of wooden tubs and involvement in related initiatives.

■ Media Coverage and Photography

This process offers a valuable opportunity to witness the actual assembly of wooden tubs on-site. This is typically a non-public operation, and opportunities to cover the world of wooden tub culture firsthand are limited.

The following arrangements can be made for this initiative:

・On-site interviews (available throughout the period upon arrangement)

・Photography of the factory and brewery

・Interviews with coopers and the representative director

・Filming of the wooden tub assembly process

*Arrangements will be made upon scheduling.

Event Outline

Period: Scheduled for approximately 10 days from April 16, 2026

Location: Shibanuma Soy Sauce Brewery (Tsuchiura City, Ibaraki Prefecture)

Content: Wooden tub replacement (renewal) work

Cooper: Takeshi Ueshiba

From Fujii Seisakusho, a long-established company in Sakai, Osaka.