• Chunichi Shimbun


The first toilet seat with a built-in warm water shower-spray was released 50 years ago by Ina Seito in Tokoname, Aichi Prefecture, the predecessor of Lixil Group.

Sales were sluggish at first but the electronic toilet has grown in popularity and is now synonymous with the Japanese people’s love for cleanliness.

“For the past 50 years, we have made efforts to improve the product, thinking about the users,” said Ikuya Idota, 59, who has been engaged in the development of the product ever since he joined Ina Seito in 1976.

“When we are called in to repair toilets, I never met a customer who told us to take it with us. They all wanted us to fix it on the spot as soon as possible,” said Idota, who heads Lixil’s development team of electrical devices for toilets. “Once people realize how comfortable it is, they can’t stop using it,” he added.

In 1967, the company introduced Sanitarina 61, the first domestically produced toilet seat with a warm-water shower unit.

It was developed based on a toilet for medical use imported from Switzerland.

At the time, the company’s core strength was in tiles and it lagged behind rival companies when it came to sanitary ware.

“There was a culture in the company to let workers try new things that are different from other companies,” Idota said.

However, Ina Seito did not have enough data on the shape of human buttocks, so the team struggled with how and where to place the warm water spray.

So they created plaster molds by asking their colleagues to sit on blocks of clay.

From the variations in the molds, the product designers were able to determine the optimal position for the nozzle and the angle of the water spray.

When it was first put on the market, it was sold at ¥280,000, about half the price of a car.

It was purchased mainly by the wealthy, and the company was only selling about 100 to 200 units per month even after nine years, when Idota joined.

The toilet seat was so comfortable to use that one of Idota’s older colleagues predicted that it will eventually catch on and every household will install one in the future.

Soon after, rival companies such as Panasonic began developing their own electronic toilets, while Toto released the product under the name Washlet.

As the use of electronic toilets became more widespread, more families began installing them in their homes, just as Idota’s colleague had predicted.

With the growth in production volume, Ina Seito started developing new functions, but, time and again, the development team encountered unexpected challenges because toilet is a product used in a private space.

In 1995, the company, which had changed its name to Inax, introduced an automatic flushing function triggered when a user stands up from the seat.

However, after the new product was put on sale, many reported cases of the toilet flushing before the user finished wiping.

“We failed to take into account the fact that people adopt different postures when wiping their bottom. Some do it half-sitting, while some only raise one side. There are also people who do it while standing,” he explained.

The team had to make several adjustments after the product was launched to resolve the issue.

The team continued to innovate and implement new technologies, including sterilization, odor removal and using a smartphone in lieu of a remote controller to operate the toilet seat.

Lixil currently ships 1 million units annually, and holds 40 percent of the market in the country.

Electronic toilets have been installed in approximately 80 percent of all households nationwide. However, there are still many regions around the world where the product is not common, such as Europe.

“The technology originally came from abroad, but we have improved it for the last 50 years and now Japanese people are aware of how great it is,” said Idota. “There are still people in the world waiting for this product. We want to market it globally as a product from Japan.”

This section, appearing Tuesdays, features topics and issues from the Chubu region covered by the Chunichi Shimbun. The original article was published May 20.

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