The azuki bean (also spelled adzuki or aduki) is an annual vine, Vigna angularis, widely grown throughout East Asia and the Himalayas for its small (approximately 5 mm) bean. The cultivars most familiar in north-east Asia have a uniform red color, but white, black, gray and variously mottled varieties are also known. Scientists presume Vigna angularis var. nipponensis is the progenitor. Genetic evidence indicates that the azuki bean was first domesticated in the Himalayas. It was first cultivated in Korean peninsula and northeast of China before. It was later taken to Japan, where it is now the second most popular legume after the soybean.
In East Asian cuisine the azuki bean is commonly eaten sweetened. In particular, it is often boiled with sugar, resulting in red bean paste and a very common ingredient in all of these cuisines; it is also common to add flavoring to the bean paste, such as chestnut.