Fei Long Hua Dao (飛龍化刀)

Drawing of a Fei Long Hua Dao rocket, from 'Huo Long Jing (《火龍經》)'.

Fei Long Hua Dao (飛龍化刀, lit. 'Flying dragon turning into knives') was a highly unusual and viciously designed—if not terribly effective—rocket. Recorded in famous Ming military treatise Huo Long Jing (火龍經), it was a one zhang five fen long spear-sized rocket with a two chi long bamboo rocket motor as well as two Du Huo (毒火) poison smoke-cum-incendiary warheads, which by itself wasn't anything unusual. What set Fei Long Hua Dao apart from other rockets was that it was fitted with several secondary rockets designed to be engaged at the same time as poison smoke warheads detonate. Known as Hua Dao Tong (化刀筒, lit. 'Knife-changing tube'), these stickless secondary rockets were two chi five cun long gunpowder-filled tubes fitted with three poisoned blades on both ends, and were said to be able to cover an area dozens of zhang wide, literally shredding anything they hit.

Long Fei Hua Dao Zhen (龍飛化刀陣)

Layout of Long Fei Hua Dao Zhen, from 'Huo Long Jing (《火龍經》)'.

The author of Huo Long Jing also created a military formation for the rocket, called Long Fei Hua Dao Zhen (龍飛化刀陣, lit. 'Dragon flying changing into knives formation') or simply Long Fei Zhen (龍飛陣, lit. 'Dragon flying formation'). The formation was designed to inflict maximum mayhem with the rockets to create an opening that allowed a trapped unit to break out of encirclement, and was best deployed during cloudy but windless weather.

Long Fei Hua Dao Zhen consisted of thirty-two rocket teams armed with ten Fei Long Hua Dao rockets each. These rocket teams were arrayed in a checkerboard-like formation, with eight teams serving as vanguard, twelve teams as wings, four teams at the centre, as well as eight teams as rearguard. Nevertheless, it was not known what purpose such a specific formation served other than for firearms safety, as Fei Long Hua Dao had a long enough range that such arrangement wouldn't be necessary.