《明史·志·卷六十五》
皇帝出征，皇帝的大营便位于正中，五军分别驻扎在四周，步兵在肉骑兵在外，骑兵之外是神机营，神机营之外是长围，方圆二十里，在这中间割草打柴。
大驾征行，则大营居中，五军分驻，步内骑外，骑外为神机，神机外为长围，周二十里，樵采其中。
When the emperor went on a military campaign, the emperor's main camp would be located in the center, with the five armies stationed around it, infantry inside the cavalry, and the Shenji Battalion outside the cavalry and outside the Shenji Battalion would be a large perimeter of about 40 miles, and inside it grass could be cut and firewood could be collected.