Black rice is also known as black japonica rice, japonica rice is not the same as glutinous rice. Black glutinous rice is with purple-red seed coat of rice, because the rice quality has glutinous, so it is also known as blood glutinous rice, natural blood glutinous rice after soaking in warm water, due to the red pigment of the seed coat is slowly dissolved by the aqueous solution, it will gradually appear purple-red aqueous solution, with the extension of time, the red color is more and more intense. And after cooking, the red seed coat will be separated from the embryo (rice grain). Counterfeit blood glutinous rice is made from poor quality rice, colored by purplish red pigment. The most obvious difference is that after soaking in water, the water quality becomes red significantly faster than the real blood glutinous rice, more than a few washes will reveal the original shape of white rice, and no red seed coat appears after boiling. Glutinous rice is sticky.