Art of War 12.2

Ts‘ao Kung thinks that 姦人 “traitors in the enemy’s camp” are referred to. He thus takes 因 as the efficient cause only. But Ch‘ên Hao is more likely to be right in saying: 須得其便不獨姦人 “We must have favourable circumstances in general, not merely traitors to help us.” Chia Lin says: 因風燥 “We must avail ourselves of wind and dry weather.”

煙火 is explained by Ts‘ao Kung as 燒具 “appliances for making fire.” Tu Mu suggests 艾蒿荻葦薪芻膏油之屬 “dry vegetable matter, reeds, brushwood, straw, grease, oil, etc.” Here we have the material cause. Chang Yü says: 𫎓火之器燃火之物 “vessels for hoarding fire, stuff for lighting fires.”