《宋史·志·卷四》
又说是日月星三光的通道，主管侦察关隘桥梁及国内外的边境。
又曰三光之道，主伺候关梁中外之境。
It is also said to be the passageway of the sun, moon, and star tri-lights, in charge of investigating passes, bridges, and borders between countries.