Washlet

Washlet (ウォシュレット, Woshuretto^?) is a registered trademark of the Japanese toilet company Toto, referring to electric toilet seats with water spray feature for genital and anal cleansing. It falls into the category of "electronic bidets" and is commonplace at toilets in Japan. The buttons associated with operating the cleansing features are labeled "oshiri" (bottom) and "bidet". Some models have a sensor that prevents spraying water when a person is not sitting on the toilet. In order to determine the appropriate spray position, Toto surveyed 300 male and female employees during development. Released in June 1980, a total of more than 30 million washlets have been sold by January 2011. Washlets have a large share in the cleansing toilet seats market and have such a wide reputation that similar products from other toilet manufacturers like INAX (currently LIXIL. Their product is named “shower toilet”) are also colloquially referred to as washlets, even though “washlet” is a registered trademark of TOTO.

TOTO’s business model in the 1960s was to import American “wash air seats” for domestic sales. They were mainly sold to hospitals for medical purposes and nursery homes. TOTO began domestic production in 1969, but washlets were initially expensive and sometimes caused burn injuries from the inability to keep the water temperature stable. TOTO continued its research and development on its own, and banking on the prospect that washlets would widely sell in Japan which has a hygiene-oriented culture, began to sell two different types of washlets in 1980. Because there was no biological statistics available on anal positions, the company collected data with the help of employees and adjusted the position of the squirt valves. The two different types were the G series (where G stands for gorgeous) that could stock warm water, had a bidet and a dryer function, along with an ability to keep the toilet seats warm (the function of which is called warmlet), and the S series (where S stands for standard) that instantly turns cold water into warm water and is equipped with a bidet and a warmlet function. These two series have remained the basic product models until now, along with the compact series introduced in 1993. The models included a regular size and an elongate size depending on the size of the toilet to which washlets are attached, but were replaced by single-sized models in February 2012 with a few exceptions such as products for hotel usage.

...
Wikipedia