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Shuyu produced in Mingzhou
Shuyu produced in Yongkang Jun
(That is, Dioscorea opposita, also known as Shan Yu.) Sweet in taste, warm or neutral in nature. Non-toxic. Produced in prefectures across the north and south, but those from Huaiqing are superior. Harvested in autumn, dried in the sun, and stored with ash to prevent insect damage. (Stored together with wood ash in jars, they will not be damaged by insects.) Its properties are incompatible with Kansui Radix (Kansui Root), so they should not be used together in a prescription. When combined with Asparagusus Tuber (Tian Dong), Ophiopogon Tuber (Mai Dong), and Ganoderma (Zi Zhi), it enters the Taiyin channels of the hand and foot. It treats various deficiencies and hundred types of exhaustion; tonifies Qi and strength, moistens the skin, promotes muscle growth, and strengthens bones and sinews. It dispels pathogenic cold and heat, eliminates irritability and fever; expels wandering wind from the head and face, and resolves vertigo due to wind. It tonifies emaciation and reduces swelling and hardness. It opens the mind's aperture to enhance intelligence, and astringes essence to treat seminal emission and slipping. It regulates spleen injury to stop diarrhea, often added to Shen Ling Bai Zhu San; it drives away lower back pain and strengthens Yin, requiring the use of Liu Wei Di Huang Wan. Pounded into powder and made into paste, it is very sticky. Long-term consumption prevents hunger, prolongs life, and delays aging.
(Mo) Commentary: Shanyao can reduce swelling and hardness because it tonifies Qi and supplements the middle. The Classics state: Where there is deficiency, pathogens inevitably gather. If they adhere and do not depart, the condition becomes excess. Is this not referring to swelling and hardness? Therefore, by tonifying its Qi, the stagnation of pathogens naturally cannot remain and dissipates on its own. Danxi said: Substances that tonify Yang Qi and promote generation can eliminate swelling and hardness, precisely

Shihu produced in Wenzhou
Shihu produced in Chunzhou
Sweet in taste, neutral in nature. Non-toxic. Mostly produced in Lu'an Prefecture (a prefecture name, belonging to Nan Zhili), and also grows in Liangguang (Guangdong and Guangxi). The stem is small with nodes, yellowish like gold. People often refer to it as Jinchai Shihu, likely taking its shape as reference. There are two varieties, slightly different upon close inspection. Those growing on stream rocks are named Shihu, which feel solid when broken; those growing on oak trees are named Mujhu, which are hollow inside like wheat stalks when broken. Genuine Shihu has efficacy but is hard to find; Mujhu has no efficacy but is easy to obtain. Sellers often harvest the easy-to-get Mujhu to pass off as genuine, so one must take precautions. It is incompatible with Ningshuishi and Croton Seed (Badou), and fears White Stiff Silkworm (Bai Jiangcan) and Polyporus Umbellatus (Leiwan). Soaked in wine and steamed, it is suitable for inclusion in prescriptions. It calms fright and stabilizes the spirit, benefits essence and strengthens Yin. It strengthens bones and sinews, tonifies deficiency and emaciation, strengthens legs and knees, and dispels cold bi-syndrome. It expels external pathogenic heat from the skin, and clears deficient fire in the stomach. It thickens the intestines and stomach, lightens the body, promotes muscle growth, and directs Qi downward.