In fact, you can't even buy helmets in bike stores. Parking bicycles is a problem in Japan. The most crowded spots are at train stations. In general, you must park legally or the police will impound your bike. In Kyoto, if you don't retrieve an impounded bike within two or three weeks, it is literally crushed and thrown out.
Some legal spots are free, but many are paid for, either by the day or by the month.
Since they aren't common here, the police just leave bikes locked with them alone. I wonder how long this trick will survive. There were some folks already waiting in the uninsulated, unheated anteroom, huddling around a big ceramic pot with hot coals. A dozen of us took the tour, which was entirely in Japanese. For advanced warning of someone entering, the floor boards were made intentionally squeaky, and little metal pendulums went click-clack when the shoji were opened.