The Su Wen · Tiao Jing Lun （《素问·调经论》, Plain Questions · Theory of Regulating Meridians） said, ＂Patients with pain in body yet without any ailment are treated with contralateral shallow collateral needling; patients with pain on one side with ailments on the other side are treated with contralateral deep collateral needling＂. Therefore, both of the two therapies are applicable to pain syndromes, and, for contralateral deep collateral needling, the pulse manifestation on the healthy side is different from that on the diseased side. Contralateral shallow collateral needling and contralateral deep collateral needling are the therapies where the right side is acupunctured if the left side is diseased and vice versa. It follows that the below side is acupunctured if the upper side is diseased and vice versa. The therapeutic principle is based on inducing yin from yang and vice versa. As cited from the Suwen （ 《素问》, Plain Questions）, ＂A good acupuncturist follows the policy of ＇knowing yourself and knowing your enemy＇, and he/she tends to treat the yin disease from the theory of regulating yang, treat the disease on the left side by regulating the right side and vice versa, he/ she knows to learn the inner disorder from the outer and knows to learn the future disease by the hints＂.
