Chang Yü says: 九地之法不可拘泥 “One must not be hide-bound in interpreting the rules for the nine varieties of ground.

the expediency of aggressive or defensive tactics;

The use of 屈伸 “contraction and expansion” may be illustrated by the saying 屈以求伸, which almost exactly corresponds to the French “il faut reculer pour mieux sauter.”[[182]] Capt. Calthrop, more suo, avoids a real translation and has: “the suiting of the means to the occasion.”

and the fundamental laws of human nature: these are things that must most certainly be studied.

42. 凡爲客之道深則專淺則散

When invading hostile territory, the general principle is, that penetrating deeply brings cohesion; penetrating but a short way means dispersion.

Cf. supra, [§ 20].

43. 去國越境而師者絶地也四達者衢地也

When you leave your own country behind, and take your army across neighbouring territory,

Chang Yü’s paraphrase is 而用師者.