39. 焚舟破釜若驅羣羊而往驅而來莫知所之
He burns his boats and breaks his cooking-pots;
Omitted in the T‘u Shu.
like a shepherd driving a flock of sheep, he drives his men this way and that, and none knows whither he is going.
The T‘u Shu inserts another 驅 after 羊. Tu Mu says: 三軍但知進退之命不知攻取之端也 “The army is only cognisant of orders to advance or retreat; it is ignorant of the ulterior ends of attacking and conquering.”
40. 聚三軍之衆投之於險此謂將軍之事也
To muster his host and bring it into danger:—this may be termed the business of the general.
Sun Tzŭ means that after mobilisation there should be no delay in aiming a blow at the enemy’s heart. With 投之於險 cf. supra, [§ 23]: 投之無所往. Note how he returns again and again to this point. Among the warring states of ancient China, desertion was no doubt a much more present fear and serious evil than it is in the armies of to-day.
41. 九地之變屈伸之利人情之理不可不察也
The different measures suited to the nine varieties of ground;