Acupuncture--a method of relieving pain and treating illness--was perfected during Song times. Needles inserted at certain points on the body are thought to cure all sorts of illnesses, from arthritis to poor eyesight. The Chinese believe that an ill-force flows through the body along definite paths. When the flow is blocked, or when the forces of ying and yang are out of balance in the body, the needles are used to restore good health.