A range of plants in a variety of regions around the world have been used to produce indigo dyes, each with its own unique approach. However, in Japan the most well known is called awa-ai, and, as the name implies, it is produced in the Awa region of eastern Shikoku known as Tokushima. The plant grown there is called tadeai. The leaves are harvested, dried, and composted to create what is called sukumo – the basis of Japanese indigo vat dyeing. The composted material is then tamped down in a large mortar, or made into a thick paste and dried. The dried cake is called aidama. It's easy to store and transport. Nowadays the moister version, sukumo, is used by most dyers. In Okinawa, China, and India the preferred method is to create an indigo lake (chinden-ai) after first fermenting the indigo leaves.