Aa per
Reasearchgate paper,
Azuki (
Vigna angularis var.
angularis) is regarded to have been domesticated in China, Manchuria, Korea or Japan from its wild ancestral form,
Vigna angularis var.
nipponensis (Ohwi) Ohwi & Ohashi. Recently, the natural distribution of Vigna angularis var. nipponensis was reported to be wider than recognized before, ranging from Japan, Korea, China to Himalaya (Tibet, Bhutan, Nepal). Almost all global production of azuki occurs in four countries: Japan, China, Taiwan, and South Korea.