China's new national standard clearly stipulates the classification of edible commercial rice: indica rice and japonica rice are divided into one, two, three and four grades; Indica rice, japonica rice, high-quality indica rice, high-quality japonica rice, high-quality indica rice and high-quality japonica rice are divided into three grades: one, two and three. First-class rice: there is no skin on the back groove, or there is skin and no grain, and more than 90% of the rice embryo and rice grain surface cortex is removed; Second-class rice: there is skin on the back groove, and the rice embryo and grain surface cortex are removed, accounting for more than 85%; Third-grade rice: there is skin on the back groove, and less than one-fifth of the grain surface cortex remains, accounting for more than 80%; Grade 4 meters: there is skin on the dorsal sulcus, and less than one third of the grain surface cortex remains, accounting for more than 75%.