Yao Wang means “medicine king”, yao being herbal medicine and wang the word for king. It is where Sun Simiao, one of the greatest doctors in history, retired to a mountain in central Shaanxi, on the outskirts of Tongchuan. He was born in neighbouring Shanxi in the 580s, but travelled extensively and eventually retired to Yao Wang. He died there in 682 AD.
Many of his insights were original and correct. One tiny example: he recognized that goitre (when the thyroid gland causes the neck to swell) was mainly caused by iodine deficiency. Shaanxi is far from the sea and mountainous, so he correctly prescribed the use of seaweed for its high iodine content.
One chapter of the many volumes of medicine and philosophy, and studies of Taoism and Buddhism, provides a still-used ethical pronouncement which is comparable to the more ancient Hippocratic Oath.
His words are full of real wisdom: