Because homes in Japan are tiny, every square centimeter of space counts. This CU11 chair was designed with no back; instead it's meant to be placed right up against a wall, letting the wall provide the backrest.
The chair was specifically designed for elderly users, to provide seating while they don and doff their shoes. It's meant to be placed at the entryway of homes. The seat is wider than average, and there's a flip-out hook under the armrest to hold a cane or walking stick.