For footwear purposes, the border between inside and outside is not the door itself, but the entrance area, called genkan. Although located indoors, the genkan is still considered outside and is the place for people to take off and put their shoes. In contrast, the indoor space is typically elevated and covered by a different type of flooring than the genkan. Make sure not to step onto the genkan after taking off your shoes. It is considered good manner to turn your shoes to point towards the door after you have removed them.
