Company history - Nihon Koken Kogyo Co., Ltd. - Pearlescent pigment

After the war ended, Yoshio Fujioka, the Director of the Institute for Optical Research affiliated with Tokyo Bunrika University (later Tokyo University of Education), decided that Japan urgently needed to acquire foreign currency for trade. His judgement resulted from investigation into various research areas connected to Japan's recovery. Fujioka began researching into and developing pearlescent pigment, which is the raw material for artificial pearls, and appointed Sei Hachisu as his assistant (at the time). By researching the properties of fish scales, Hachisu discovered the necessary conditions for pearl pigment. He began researching and developing chemical compounds that would satisfy these conditions.

In 1946, Sei Hachisu, Tadashi Miyazaki, and their team established a method for producing fish scale foil by purifying pilchard scales. In March 1949, the same team successfully generated crystallized lead thiosulphate to create Synthetic Pearlescent Pigment Mark One. As this product was received to great acclaim by the imitation pearl industry, the then Chairman of the Imitation Pearl Industry Association Wakanobu Yoneda recognized the need for these results. Collaborative research into pearl foil was proposed and a request was made for financial support. However, the Mark One Foil had poor light stability and was never put into practical use. The Mark Two Foil was made from barium thiosulfate. However, its luster was not bright enough and it was not possible to use the Mark Two as a pearlescent pigment either. The research team members were Akira Kose, Satoshi Shiohara, Tetsuya Ichimaru, and Tsunehiro Odaka, working under the direction of Hachisu.

The reserach team was extremely constrained by time and financial resources but, with determined resolve, they embarked up their next research project. By looking into lead compounds from the perspective of refractive indexes, the team discovered a method of precipitating crystals for the Mark Three Foil (lead carbonate basic foil). In 1951, they gained subsidies from the Ministry of Education, Culture, Sports, Science, and Technology and began to investigate how they would mass produce the product. The following year, they established and developed an interim pilot plant. In just over a year, the team achieved their original objective. After that, Seiichi Mori and Kichio Igawa joined the project in quick succession.