Those are Curly Hazelnut branches. You can get a bundle of them at Wal-mart for about $10. In a Japanese bathroom, (or any that you see without shower curtains or doors), the whole floor has to be covered with waterproof concrete, tile or stone, then waterproofed grout. This must be done by a professional, since the floor has to have drains all along one side and be designed to slope towards the drains. In Japan, it's traditional to get washed sitting on a stool outside the tub, or to take a shower before getting in the bath. That way, the whole family can take turns soaking in the tub without having to change the water, because filling such a huge tub uses a LOT of hot water. Some neighbourhoods still have community baths, where neighbours get together to relax in giant, shared tubs and chat. The tub is not used for getting clean, but just for relaxing. And YES, everybody gets naked to do this, although some community baths have separate times for men and women.