A woodcut showing acupuncture points on the face, neck, shoulder and hand, annotated in Japanese characters. From "Kana yomi jushikei" (a treatise on acupuncture), Osaka, 1805. In traditional Chinese medicine, illness is considered to be due to an imbalance of "vital energy" or Ch'i which flows through the body along twelve pathways or meridians each of which corresponds to one of the vital organs. The acupuncturist corrects the imbalance by inserting needles at specific points on the meridians to stimulate the energy flow.