Grains include: wheat, rice, millet, sorghum, soybeans and other food crops. In ancient times, there were two kinds of grains, one was glutinous rice, millet, wheat, rice and millet, and the other was glutinous rice, millet, wheat, hemp and millet. The main difference between the two is rice and hemp, the former has rice without hemp and the latter has hemp without rice. Now the five grains are simplified as food crops, that is, wheat, rice and small crops.