In the fall of 1965, a dozen or so toilets were installed on the roof of the Osaka Plant. Those who did not know what was transpiring whispered "What in the world is going on?" to each other. The spectacle of so many toilets lined up in a location that was not a restroom was certainly unusual. Paying no heed to these comments, Masafumi Ozaki and others from the Development Section (at the time the Research Division) were struggling with "colored water". The development of the prototype of the toilet deodorant, cleanser, and soil-repellent later named "Bluelet", of which a similar product was being sold in the United States, was underway.

There was a decisive difference, however, between American toilets and those of Japan. In the U.S., most wastewater was flushed to sewers after use. In Japan there were many more processes involved, such as septic tank accumulation, filtering, and waste removal. Live bacteria were used in septic tanks, precluding the use of chlorine. Since the U.S. did not have such restrictions, however, chlorine substances were being used as the primary ingredients. So although they were similar products, they were also completely different.

Additionally, each time problems with usage arose during development, the liquid dissolution quantity and the color and scent always needed to be constant. Variations in color and scent meant a defective product. Furthermore, the water temperature of toilet tanks was not constant among different regions, nor were tanks used at fixed periodic intervals. There were both warm and cold regions. And while the frequency of usage was high in areas housing a large number of families, usage of once or twice a day for single persons or non-use periods of about one week for those who traveled were not uncommon. Regardless of the circumstances, ensuring the consistency of the color and scent of tapped water proved to be unexpectedly difficult. Everyday, Ozaki and his staff of 7 to 8 manufactured trial products, tested them out on the rooftop, made improvements to deficiencies, and returned to the roof again.

After half a year had passed and the one-year point was drawing near, they succeeded in color consistency for the first time. Since development had started, the staff celebrated what could be called their first success at a nearby pub. It was the only day they were able to take a long-deserved break and enjoy themselves leisurely. Somehow, there had to be something that could be done about the scent. There was also the problem of water temperature. If these hurdles could be cleared, there was then the challenge of manufacturing method and cost.

Anmerts, which began development later, had surpassed them, yet still their goal was not in sight. There were periods when they seemed to have become pessimistic. At such times, Supervisor Tatsumi Baba and Managing Director Takeshi Ninomiya visited the staff to provide encouragement. And Kazumasa Kobayashi (the present-day President), who returned from the United States in 1966 and was named Chief of the Development Section, was encouraged by the difficulties he faced together with the development staff.

"Bluelet" was completed in the spring of 1969. After a period of about four years from the start of development and with huge investments in costs and human resources, a product that had not previously existed in Japan had been completed.