"The restroom that's partly visible in the previous picture. Formerly a Japanese-style toilet [example shown top-left], forcibly converted to a western-style one. I would've been perfectly fine with the Japanese-style toilet, but I guess this would probably be preferable for most of my probable visitors."
The standard flush toilet used worldwide is known in Japan as a Western-style (yoshiki), while traditional units are known as washiki, requiring a squatting position that we never really got used to during our trips to Asia (it explains the phenomena known as the "Asian Squat").
A squat toilet essentially looks like a miniature urinal rotated 90 degrees and set into the floor. Most squat toilets in Japan are made of porcelain, though in some cases (like on trains), stainless steel is also used. Instead of sitting, the user squats over the toilet, facing the hemispherical hood, i.e., the wall in the back of the toilet in the picture seen on the right. - Toilets in Japan
Personally, I'd prefer one of Japan's more modern contributions to modern plumbing, the Toto NeoRest.