《管子·七法》
所以，用兵这件事情，一定要详审地理情况，掌握天时，计算军需贮备，教练勇士，普遍掌握天下的情况，认真抓好战机和运用策略。而这些也正是统帅的本职。
日量蓄积，齐勇士，遍知天下，审御机数，兵主之事也。
Therefore, in the matter of using troops, one must carefully examine the geographical conditions, grasp the right time, calculate the military supplies, train the warriors, generally grasp the situation in the world, and carefully seize opportunities and use strategies. And these are the basic tasks of a commander.