December 05, 2025
【Sustainable Japan Excellence Award】Yamaroku Shoyu Co., Ltd.
We are honored to receive the Excellence Award in the satoyama category of the Sustainable Japan Award for our Kioke Craftsmen Revival Project.
Kioke — large wooden vats once indispensable to traditional soy sauce brewing — were a familiar sight in breweries across Japan for centuries. Made from Japanese cedar and bound with bamboo hoops, these vats imparted subtle aromas and flavors that cannot be replicated by modern steel tanks. However, as the brewing industry shifted toward cheaper, more efficient tank production in the mid-20th century, the use of kioke rapidly declined. Today, they account for only about 1% of soy sauce production in Japan. Compounding this decline, the number of skilled craftsmen capable of making and repairing these vats has dwindled sharply, with most now in their 70s or 80s.
Recognizing this as a cultural and culinary crisis, we have joined forces with breweries, artisans and supporters nationwide to train new craftsmen, pass down traditional vat-making techniques and share the appeal of kioke brewing with audiences both in Japan and overseas. In the spirit of preserving true tradition through industrywide cooperation beyond regional borders, even competing companies have collaborated on this forward-looking initiative.
We see this award as an acknowledgment that our work helps sustain not only a craft, but also the natural environment, local communities and Japan’s culinary heritage. We will continue to walk alongside the kioke makers so that future generations — our children and grandchildren — can inherit this authentic tradition.
We extend our deepest gratitude to all who have supported our journey.
Reason for the award:
Yamaroku Shoyu has played a vital role in preserving the centuries-old tradition of wooden barrel fermentation, safeguarding both Japan’s culinary heritage and its artisanal techniques. Under the leadership of fifth-generation brewer Yasuo Yamamoto, the Kioke Craftsmen Revival Project was launched to rescue the nearly vanished craft of barrel-making. Using domestically sourced materials such as Yoshino cedar from Nara, the initiative has brought together master artisans, students and residents of the island of Shodoshima to rebuild barrels and pass down essential skills to future generations.
Wooden barrels are not only vessels but living environments that nurture unique microbial ecosystems, producing soy sauce with unmatched depth of flavor while supporting broader fermentation traditions, including miso and vinegar. To raise awareness, Yamaroku also organizes the Kioke Fermentation Culture Summit in cities nationwide, expanding recognition beyond Shodoshima.
Despite fierce price competition in the soy sauce market, the company continues to emphasize quality and cultivate loyal fans, seeking to expand the niche market for barrel-fermented soy sauce. Yamaroku’s efforts represent more than preservation — they embody a forward-looking revival that blends tradition with contemporary innovation, offering a model of sustainability and cultural resilience that resonates far beyond Japan.
