Ink drawing from a MS of the Qing period (1644-1911). The Eight Extraordinary Channels (Qi jing ba mai) are distinguished from the twelve primary channels. They comprise dumai (Governor Vessel), renmai (the Director Vessel, often translated as Conception Vessel), chongmai (Penetrating vessel), daimai (Belt Vessel), Yangqiao mai (Yang Heel Vessel), Yinqiao mai (Yin Heel Vessel), Yangwei mai (Yang Tie Vessel) and Yinwei mai (Yin Tie Vessel). These eight channels are not linked to specific viscera; they form a network connecting the Twelve Channels, and serve to regulate Qi within the 'regular' channels (zhengjing).The chart shows the eight Meeting Points (huixue) of the Eight Extraordinary Channels, i.e. lieque (Break in the Sequence), neiguan (Inner Pass), waiguan (Outer Pass), houxi (Back Stream), shenmai (Extending Vessel), linqi (Close to Tears), zhaohai (Shining Sea) and gongsun (Grandparent and Grandchild).