Engadget gets to the bottom of Japanese toilets in this article.
Dirt, stains, effluent, material, the load, waste, matter. These are the words my tour guides at Toto’s toilet factory and research center in Kyushu used to verbally pirouette around what exactly its porcelain thrones deal with: shit. Japanese toilets are probably the best in the business at getting rid of your business, but for many Westerners, that first moment of contact can be terrifying. There are so many buttons, so many unknown symbols and open-to-interpretation stickmen figures; not to mention the (unfounded) fear that you could be sprayed with toilet water by merely approaching one.