Kautilya's Arthashastra 7.13.6

7.13.6

śūnyamūlo hy asya sukaro bhavati, naikadeśabalaprayātaḥ kṛtapārṣṇipratividhānaḥ //

Preparations being equal, he who captures the rear of one who has marched out with all the resources gains more advantages; for one whose base is undefended is easy to be subdued, but not one who has marched out with a part of the army after having made arrangements to defend the rear.