《黄帝内经·素问·阴阳类论》
三阳为表，二阴为里，一阴为阴气之最终，是阳气的开始，有如朔侮的交界，都符合于天地阴阳终始的道理。
三阳为表，二阴为里，一阴至绝，作朔晦，却具合以正其理。
The Three Yang are the Exterior, the Two Yin are the Interior, the One Yin is the ultimate of Yin Qi, the beginning of Yang Qi, they are like the juncture of the last day of the old moon and the first day of the new moon, they all are in line with the principle of the Beginning and the End of Yin and Yang in Heaven and Earth.