"Five Grains" is spoken in the Spring and Autumn Period and the Warring States Period. "The Analects of Confucius": "The four bodies are not diligent, and the grains are not divided." But there are different explanations. One is millet, millet, wheat and rice. Speaking of millet, millet, wheat, millet, marijuana. The main difference between these two statements is whether there is rice or hemp. The reason for the inconsistency was that there were more than five kinds of crops at that time, as evidenced by the existence of the theory of "100 grains", "6 grains" and "9 grains", and the varieties of crops were different from place to place. The popularity of the theory of "five grains" is obviously caused by the influence of five elements. Therefore, generally speaking, grain refers to several major food crops.
In Huangdi Neijing, five grains are called "japonica rice, adzuki bean, wheat, soybean and millet"; Mencius and Teng Wengong called grains "rice, millet, millet, wheat and glutinous rice" (glutinous rice is the general term for beans); In Buddhist sacrifices, it is also called "barley, wheat, rice, adzuki bean and flax". At present, the five grains usually refer to: rice, wheat, soybeans, corn, potatoes, and grains other than rice and flour are called miscellaneous grains.
Therefore, throughout the ages, whole grains contain beans. Mung beans, red beans and black beans all belong to beans, so they belong to the category of whole grains.