[T’sao Kung thinks that "traitors in the enemy’s camp" are referred to.
But Ch’en Hao is more likely to be right in saying: "We must have
favourable circumstances in general, not merely traitors to help us."
Chia Lin says: "We must avail ourselves of wind and dry weather."]
the material for raising fire should always be kept in readiness.
[Tu Mu suggests as material for making fire: "dry vegetable matter,
reeds, brushwood, straw, grease, oil, etc." Here we have the material
cause. Chang Yu says: "vessels for hoarding fire, stuff for lighting
fires."]