Message
Message from the Representative Director
Diasalt was established in September 1955 as part of an effort to diversify operations by Mitsubishi Mining Company, Ltd. (currently Mitsubishi Materials Corporation). The Sakito Plant, our manufacturing base, is located in Sakito, Saikai, Nagasaki. Operating in the rich natural environment of the Goto-nada Sea, our mission is to deliver salt—one of the sea’s many blessings—of the highest quality and in a stable supply. The salt we provide, an essential element of life, has contributed to the development of people’s health and food culture. In addition to producing made-in-Japan salt, we also develop and manufacture a variety of salt products in a fully user-first approach. One of our leading products is the highest-quality washed sun-dried salt in the country (Hidamari no Dia; “Sunny Dia”), which we brought to market in FY2026. With that rollout, we now have a system that allows us to contribute to the salt industry from a BCP perspective by supplying both Sunny Dia and conventional made-in-Japan salt in the event of a domestic emergency.
Furthermore, we produce high-quality chemical products (potassium chloride, etc.) from bittern, a by-product of the salt-manufacturing process, to meet customer needs. This range of products, too, provides solutions to the food-additive field, industrial sphere, medical raw-material industry, and other areas. Drawing on our technical prowess in manufacturing chemical products, we are also developing and pioneering new chemical products so that we can continue to respond to customer demand.
After leaving the Mitsubishi Materials Group in March 2023, we had been operating as an independent company under a new shareholder, a fund. As of May 7, 2026, however, Japan Salt Co., Ltd., a general salt trading company, became our shareholder. That shift will help us optimize our value chain of development, manufacturing, sales, and distribution, putting us in even better position to take the user-first approach to new heights.
We will continue to aim for further growth as a leader in seawater resources, live up to the trust and expectations of society, and contribute to healthier, richer lives.
Naotoshi Kumano, President and Representative Director
Philosophy
Corporate philosophy
By delivering the highest-quality products made from the precious gift from the Goto-nada Sea, we contribute to the health and well-being of people and to a more prosperous society.
Profile
Company profile
Company overview
| Trade name: | DIASALT CORPORATION |
| Established: | September 7, 1955 |
| Capital: | 250 million yen |
| Shareholder: | Mirai no Shioya Co., Ltd. (wholly owned by Japan Salt Co., Ltd.) |
| Head Office: | 812-0027 Shimokawabata Redevelopment Bldg. 11F, 3-1 Shimokawabata, Hakata Ward, Fukuoka City, Fukuoka, Japan |
| Plant: | 857-3101 1517-3 Kakinourago, Sakito, Saikai, Nagasaki, Japan |
| Main business: | Manufacture and sale of salt Manufacture and sale of potassium chloride, magnesium chloride-containing products (bittern), etc. |
| Registration information: | Salt Manufacturer Registration No. 1, Fukuoka Local Finance Bureau Salt Wholesaler Registration No. 32, Fukuoka Local Finance Bureau Additive Manufacturer Registration No.: Nagasaki Prefecture Directive No. 4-Seihi-Ei-1366 |
| Certification information: | [Certification Information for Sakito Plant] ■Quality Management Systems ISO 9001 certification Certification Registration No. JQA-QM4503 ■Environmental Management Systems ISO 14001 certification Certification Registration No. JQA-EM1633 ■Halal Certification Japan Halal Association ID4310314 |
| Officers: | Hiroshi Okawa, Chairman and Representative Director Naotoshi Kumano, President and Representative Director Masayuki Kogushi, Senior Managing Director Fumihiko Yamada, Managing Director Hideaki Yamaguchi, Managing Director Naoko Furumi, Managing Director Toshinori Mukae, Director Shu Ogawa, Director Kunito Komatsu, Auditor Akihiro Ogata, Auditor (As of May 7, 2026) |
History
| 1955 | Sakito Salt Co., Ltd. established |
| 1972 | Ion-exchange membrane electrodialysis tank installed Capital increased from 100 million yen to 200 million yen |
| 1982 | Fukuoka Sales Office opened |
| 1984 | Coal fluidized-bed boiler installed |
| 1985 | Ryoen Co., Ltd. (special salt manufacturing and sales company) established |
| 1989 | Fukuoka Sales Office renamed Fukuoka Branch Chemical Products Division transferred from the parent company (currently Mitsubishi Materials Corporation) to the Company |
| 1990 | Capital increased from 200 million yen to 250 million yen |
| 1995 | Company name changed to Diasalt Corporation |
| 2000 | ISO 9001 certification acquired |
| 2001 | ISO 14001 certification acquired |
| 2004 | Kansai Sales Office opened |
| 2005 | Hokkaido Sales Office opened |
| 2007 | Kansai Sales Office renamed Osaka Branch 5% investment received from Mitsubishi Corporation (Mitsubishi Materials: 95%) |
| 2020 | Osaka Branch and Hokkaido Sales Office integrated into Tokyo Branch and Fukuoka Branch Special salt manufacturing operations transferred from Ryoen Co., Ltd. |
| 2022 | Diasalt Research Laboratory established |
| 2023 | All shares acquired by IA Partners Inc. Head Office relocated to Fukuoka (Tokyo Head Office and Fukuoka Branch integrated) |
| 2025 | Merged with Ryoen Co., Ltd. |
| 2026 | All shares acquired by Mirai no Shioya Co., Ltd. |
Access
Access
Head Office:
812-0027
3-1 Shimokawabata, Hakata, Fukuoka, Fukuoka, Japan
Shimokawabata Redevelopment Bldg. 11F
Phone: 092-402-1393
Fax: 092-402-1398
Sakito Plant:
857-3101
1517-3 Kakinourago, Sakito, Saikai, Nagasaki, Japan
Phone: 0959-35-2043
Fax: 0959-35-2229
Office/Laboratory:
857-3101
1393-14 Kakinourago, Sakito, Saikai, Nagasaki, Japan
Phone: 0959-35-2345
Fax: 0959-35-2748
Distribution centers
Rumoi, Kushiro, Ishikari, Hakodate, Tomakomai, Aomori, Hachinohe, Miyako, Akita, Sendai, Niigata, Naoetsu, Tokyo, Kashima, Toyohashi, Toyama, Osaka, Harima, Aioi, Hiroshima, Fukuoka, Nagasaki, Kumamoto, Usuki, Shibushi, Kagoshima, Naha
