When a general, unable to estimate the enemy’s strength, allows an
inferior force to engage a larger one, or hurls a weak detachment
against a powerful one, and neglects to place picked soldiers in the
front rank, the result must be a _rout_.
Chang Yü paraphrases the latter part of the sentence 不選驍勇之士使爲
先鋒兵必敗北也, and continues: 凡戰必用精銳爲前鋒者一則壯吾志一則挫敵威也
“Whenever there is fighting to be done, the keenest spirits
should be appointed to serve in the front ranks, both in order to
strengthen the resolution of our own men and to demoralise the
enemy.” Cf. the _primi ordines_ of Caesar (“De Bello Gallico,”
V. 28, 44 _et al._). There seems little to distinguish 北 from 走
in § 15, except that 北 is a more forcible word.