- 行火必有因煙火必素具
- 發火有時起火有日
and Chang Yü, of whom the last-named says: 焚其隊仗使兵無戰具 “burning a regiment’s weapons, so that the soldiers may have nothing to fight with.” That leaves only two solutions open: one, favoured by Chia Lin and Ho Shih, is to take 隊 in the somewhat uncommon sense of “a road,” = 隧. The commentary on a passage in the 穆天子傳, quoted in K‘ang Hsi, defines 隊 (read sui) as 谷中險阻道 “a difficult road leading through a valley.” Here it would stand for the 糧道 “line of supplies,” which might be effectually interrupted if the country roundabout was laid waste with fire. Finally, the interpretation which I have adopted is that given by Tu Yu in the T‘ung Tien. He reads 墜 (which is not absolutely necessary, 隊 chui being sometimes used in the same sense), with the following note: 以火墮敵營中也火墜之法以鐵籠火着箭頭頸强弩射敵營中 “To drop fire into the enemy’s camp. The method by which this may be done is to set the tips of arrows alight by dipping them into a brazier, and then shoot them from powerful crossbows into the enemy’s lines.”
2. In order to carry out an attack with fire, we must have means available.
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.”
the material for raising fire should always be kept in readiness.
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.”
3. There is a proper season for making attacks with fire, and special days for starting a conflagration.
