If you plan on using public bathroom おてあらい in Japan, bring your own hand towels. Many bathrooms do not provide air hand dryers or paper towels. You can purchase the hand sized hand terry cloth towels at 100 ¥ (dollar stores).
If you need to ask where a bathroom is, you will say, "otearai wa doko desu ka?" お手洗いはどこですか？ (oh te ari wa doe ko des ka?)
You will also find 'cold' as the only water temperature option.
Pubic restrooms do have Western toilets. The stall doors will have an icons of Japanese or Western toilets. In fancier places there are very fancy Western toilets. They have heated seats and built in bidets with warm and cold water temperature options.
In homes, the toilet has a separate room from the sink and shower. There are little hand washing sinks on the lid of the toilet tanks. To enter the toilet room, you will slip off house slippers and slip on special plastic slippers.
By the way, hand washing is BIG deal in Japan. They even have hand washing stations in McDonalds and mall food courts.