climbed up a height and then kicks away the ladder behind him. He
carries his men deep into hostile territory before he shows his hand.
[Literally, "releases the spring" (see V. § 15), that is, takes some
decisive step which makes it impossible for the army to return—like
Hsiang Yu, who sunk his ships after crossing a river. Ch’en Hao,
followed by Chia Lin, understands the words less well as "puts forth
every artifice at his command."]