Zori are sandals similar to what are known as flip-flops in the West. They are the most ancient form of footwear in Japan. Flat straw sandals with a thong held between the toes were already being worn in the Heian period (794–1185). Today zori are often made of lacquered lightweight wood, plastic, or rubber, and the thongs are made of cotton or velvet.
Zori are worn over tabis, which are cotton socks designed to accommodate the thong by having the big toe in a separate compartment. The zori can be easily slipped off before entering the house, with its woven floors, in keeping with the Japanese tradition of removing footwear.
During World War II (1939–45), American soldiers fighting in the Orient were told that they could tell the difference between Korean people who spoke Japanese and native Japanese by looking at the feet: the native Japanese person would have a larger space between the first two toes, for the zori worn from a young age have a marked effect on the foot, pushing the big toe and the toe next to it farther apart.
Japanese Costume Through the Ages. Tokyo, Japan: Tokyo National Museum, 1962.
Kennedy, Alan. Japanese Costume: History and Tradition. New York: Rizzoli, 1990.