Stone and bone needles found in ancient tombs led Joseph Needham to speculate that acupuncture might have been carried out in the Shang dynasty.[9][10] But most historians now make a distinction between medical lancing (or bloodletting) and acupuncture in the narrower sense of using metal needles to treat illnesses by stimulating specific points along circulation channels ("meridians") in accordance with theories related to the circulation of Qi.[9][10][11] The earliest public evidence for acupuncture in this sense dates to the second or first century BCE.[6][9][10][12]
The Yellow Emperor's Inner Canon, the oldest received work of Chinese medical theory, was compiled around the first century BCE on the basis of shorter texts from different medical lineages.[9][10][13] Written in the form of dialogues between the legendary Yellow Emperor and his ministers, it offers explanations on the relation between humans, their environment, and the cosmos, on the contents of the body, on human vitality and pathology, on the symptoms of illness, and on how to make diagnostic and therapeutic decisions in light of all these factors.[13] Unlike