Aizome is a Japanese name for indigo dyeing, which is a plant dyeing and the oldest dyeing technique of Japan. Aizome remains in the treasures of Shosoin (the treasure house of Todaiji temple in Nara prefecture).The oldest Aizome cloth of extant was found in a pyramid of Egypt, and it is said that the cloth was dyed in 4000 – 5000 years ago. We can learn the Aizome technique has been used since ancient times from this founding. In Japan, Aizome has more than 1000 years of history, and it is written in “The Tale of Genji.” In Heian period, the technique was almost accomplished, and spread through the country in Kamakura period. Then, the Japanese original Aizome culture came into bloom in Edo period. In Europe, the color of Aizome is called “Japan blue.” And in United States the color was named “Hiroshige blue” connected with the color of bright sky and ocean of Hiroshige Ando (the ukiyo-e artist, and also referred to as Utagawa Hiroshige). Now it is the representative color of Japan. It can be said that Ai is the color of Japan, has no time barrier. Hon Aizome uses 100% natural dyestuff made from plants. Water pepper, the material of Aizome dyestuff is a plant of the family Polygonaceae. Bright sunshine, blessed rain and refreshing…water pepper that grows up in the nature is the treasure. very mysterious process of dyeing. First, the fermented leaves of water pepper are hardened, then put them into the jar in order to ferment more. When it’s fermented, green liquid comes out from the leaves. Threads/Fabrics are soaked into the green liquid, and the green threads dramatically change its color into bright blue just at the moment the threads touch the air. This dramatic moment is called “aerial oxidation” and it is making the attraction of Aizome more mysterious. The numbers of soaking thread/fabric into the dye liquor determines the lightness and shade of Aizome. You need to soak thread/fabric into the dyestuff for 10 – 15 times to make an indigo blue. Today, the colour(Ai)still plays a central role – the official logo of the upcoming Tokyo 2020 Games.