Ako Kasei Co., Ltd.

Liquid bittern obtained as a by-product of seawater salt production. Primarily magnesium chloride (60–95%) with minor calcium and potassium. Indispensable as the coagulant for traditional Japanese tofu, and increasingly used as a magnesium-supply ingredient in hot-pot soups, beverages, and cosmetics. Domestic production is concentrated in Okinawa (Ishigaki, Miyako), the Seto Inland Sea (Ako, Kagawa), and Noto Peninsula. Mass-volume nigari for tofu manufacturing flows through cooperatives, while specialty single-origin nigari has emerged as a premium retail and wellness category.

Deep ocean water sourced 300–600 m below the surface off Cape Muroto in Kōchi. Stable temperature, mineral balance (Mg-rich), and low bacterial load make it a high-grade ingredient for cosmetic moisturisers, mineral beverage, and salt production. Kōchi Prefecture's Muroto and Aki facilities are the largest commercial deep-sea-water sources in Japan; Toyama Bay and Okinawa Kume Island also produce. Branded retail mineral waters and cosmetic moisturising lines have built a multi-decade premium category around the Muroto label specifically.