Highlights

• After aging in wooden barrels on land, each bottle is sealed and lowered to the seafloor of Yuasa Bay — 15 meters below the surface — where it rests for a minimum of six months while the constant, gentle undulation of the ocean waves continues the maturation process in a way no land-based cellar can replicate
• During its time on the seafloor, each bottle becomes home to barnacles and other marine organisms, which attach naturally to the glass and create a surface pattern that is different on every single bottle — no two are alike anywhere in the world
• Brewed from naturally cultivated soybeans and wheat (zero pesticides, zero fertilizers), with Nagasaki sea salt and rice, aged first in wooden barrels on land — the seafloor submersion is the final stage of a production process that begins more than a year before the bottle reaches you

Details

• Common Product Name: Kaichu Jukusei Shoyu (海中熟成醤油) — Ocean-Matured Soy Sauce
• Net Volume: 200ml (6.8 fl oz)
• Ingredients: Soybeans (Hokkaido, Japan — naturally cultivated), wheat (naturally cultivated), salt (Nagasaki, Japan), rice
• Allergens & Properties: Contains Soy, Wheat. Additive-free. No preservatives. Natural cultivation base ingredients. Each bottle is unique.
• Shelf Life: Approx. 24 months (unopened)
• Storage: Cool, dark place; refrigerate after opening
• Note on Appearance: The exterior of each bottle bears natural marine growth from its time on the seafloor. The glass itself is clean; the barnacles and organic material on the outside are part of the bottle's story and identity. Each bottle looks different. This is intentional and correct.
• Producer Name: Yuasa Shoyu Co., Ltd. (Packaging is in Japanese.)
• Producer Location: Yuasa Town, Arida District, Wakayama Prefecture, Japan; ocean aging in Yuasa Bay, Wakayama Prefecture

Producer's Story

It begins with grain that has never been touched by pesticides or synthetic fertilizers — naturally cultivated Hokkaido soybeans and wheat grown the way grain was grown before modern agriculture. Combined with Nagasaki sea salt and rice, fermented in wooden barrels in Yuasa — Japan's oldest soy sauce town — the base shoyu is already exceptional. Then Yuasa Shoyu takes it further: each sealed bottle is lowered into the waters of Yuasa Bay and left on the seafloor at 15 meters' depth for a minimum of six months. Down there, in the dark and the cold, the constant movement of the ocean — the undulation of waves translated into gentle, perpetual motion at depth — continues to work on the liquid inside. The pressure, the temperature, the rhythm of the sea: all of it becomes part of the final flavor. When the bottles are brought back to the surface, each has been claimed by the ocean in its own way. Barnacles have attached. Algae has settled and gone. The glass carries a record of six months beneath the sea that cannot be manufactured or faked. There are only as many bottles as the sea returns.

Flavor Profile

Ocean aging gives this soy sauce a quality that is genuinely difficult to categorize. The base character — deep, naturally complex, with the warmth of wooden barrel and naturally cultivated grain — is familiar from the Rosanjin line. But the seafloor months add something harder to name: a mineral depth, a smoothness that seems to come from absolute stillness and absolute movement at once, a finish that is longer and more layered than any land-aged equivalent. It does not taste of the ocean, but it tastes of time — specifically, of time spent in a place where time moves differently. Side by side with any other premium soy sauce, the difference is immediate and sustained.

Cooking Ideas

A soy sauce this rare and this particular deserves to be tasted first on its own terms: a small ceramic dish, a few drops, a piece of very fresh sashimi — nothing else; the classic pairing for exceptional Japanese soy sauce remains the best introduction; used as a finishing condiment over a bowl of warm white rice to taste it plainly, before considering what else it can do; drizzled over a softly set egg dish (chawanmushi, onsen tamago, or a warm poached egg) where its complexity is the main event; a single teaspoon in a cold glass of water as a drinking vinegar style preparation — some bottles are beautiful enough that they deserve a moment on the table before they are opened, where the marine exterior can be seen and the story told to whoever is there to hear it.

✈️ Ships from Japan ·Order more, pay less per item.
Strictly limited quantities · Each bottle is one of a kind