As a tonifying herb which enters the kidney organ (Zang) and/or channel (Jing), its role is fundamental, in accordance with the dictum that "the kidney is the root of Yin and Yang of all the organs (Zang-fu).
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In this role of tonifying Qi without injuring the Yin it appears in such classical formulas as Liu Wei Di Huang Wan, 六味地黃丸, the Six Flavours Rehmannia Pill, and its many derivative and related formulas.
The economy of Tōhoku is heavily dependent on an agriculture, based primarily on production of nagaimo, daikon and carrots as well as lake fish, including smelt, icefish and shijimi.