The azuki bean (also spelled adzuki) is an annual vine widely grown throughout East Asia and the Himalaya for its small (approximately 5 mm) bean. The cultivars most familiar in northeast Asia have a uniform red color, but white, black, gray and variously mottled varieties are also known.

Genetic evidence indicates that the azuki bean was first domesticated in the Himalaya. It was cultivated in China and

Korea before 1000 BC. It was later taken to Japan, where it is now the second most popular legume after the soybean.

Names
The name azuki is a transliteration of the native Japanese name. Japanese also has a Chinese loanword, Shōzu, which means "small bean" (its counterpart "large bean" being the soybean).

In China, the corresponding name is still used in botanical or agricultural parlance. However in everyday Chinese, the more common word is hongdou, meaning "red bean", because almost all Chinese cultivars are uniformly red. In English-language discussions of Chinese topics, the term "red bean" is often used (especially in reference to red bean paste), but in other contexts this usage can cause confusion with other beans that are also red.

The Korean name is pat.

Uses

In Chinese, Japanese, and Korean cuisine the azuki bean is almost always eaten sweetened. In particular, it is often boiled with sugar, resulting in red bean paste, a very common ingredient in all three cuisines.

Red bean paste is used in many Chinese foods, such as: tangyuan, zongzi, mooncakes, baozi. It is also used as a filling for Japanese sweets such as anmitsu, taiyaki (Korean: bungeoppang), and daifuku. A more liquid version, using

azuki beans boiled with sugar, lotus seeds and orange peel, produces a sweet dish called red bean soup. Azuki beans are also commonly eaten sprouted, or boiled in a hot, tea-like drink.

In Japan, rice with azuki beans (sekihan) is traditionally cooked for auspicious occasions. Azuki beans are also used to produce amanattō, and as a popular flavour of ice cream.