The "Shennong bencao jing" ("Divine Farmer's Classic of Pharmaceutics") of c.200–250 CE, classifies "zhi" into six color categories, each of which is believed to benefit the "qi", or "life force", in a different part of the body: "qingzhi" (青芝; "Green Mushroom") for the liver, "chizhi" (赤芝; "Red Mushroom") for the heart, "huangzhi" (黃芝; "Yellow Mushroom") for the spleen, "baizhi" (白芝; "White Mushroom") for the lungs, "heizhi" (黑芝; "Black Mushroom") for the kidneys, and "zizhi" (紫芝; "Purple Mushroom") for the Essence. Commentators identify the red "chizhi", or "danzhi" (丹芝; "cinnabar mushroom"), as the "lingzhi".