Unique weapon of the Ming Dynasty — Huo Jian Liu (火箭溜)

UPDATED APRIL 29, 2022

Drawing of a Huo Jian Liu and its rack-and-pinion matchlock mechanism (highlighted), from 'Shen Qi Pu (《神器譜》)'.

China was the first civilisation in the world to field rocket weaponry in warfare. Early rocket was nothing more than a simple, black powder-filled paper tube attached to the shaft of an arrow, hence the name Huo Jian (火箭, lit. 'Fire arrow'). Although devastating, primitive unguided rocket could not be aimed like a crossbow or arquebus due to limitations of its launching platforms, and thus had pretty bad accuracy. Chinese military innovators attempted to solve this problem by developing various types of multiple rocket launchers that could shoot large numbers of rockets at once. While this "spray and pray" approach alleviated the accuracy problem somewhat, it was also very wasteful.

During the late 16th century, Ming firearms specialist Zhao Shi Zhen (趙士楨) proposed a much more refined solution to early rocket's accuracy problem in the form of Huo Jian Liu (火箭溜, lit. 'Fire arrow slide'). Huo Jian Liu was, for all intents and purposes, a matchlock gun that shot rocket instead of the usual lead ball, and featured the same barrel, front and rear sight, shoulder stock as well as trigger as an ordinary musket. However, instead of a standard matchlock mechanism, Zhao Shi Zhen equipped the weapon with a Chinese rack and pinion matchlock mechanism identical to that of late Ming variant Lu Mi Chong (嚕密銃). To ensure gunner safety, the matchlock mechanism was mounted at the middle portion of the gun (farther away from the gunner), with a large gun shield installed behind it to deflect rocket backblast.

Huo Jian Liu allowed its user to aim and launch rocket with greater accuracy. It also had greater range, less recoil, and significantly faster rate of fire than typical musket (due to the elimination of pouring powder charge, loading and ramming the ball down the barrel, and priming the flash pan steps in the reloading process). On top of that, the gun was cheaper to manufacture, as it did not need a strong barrel to withstand high chamber pressure, nor ramrod (although this was offset by its more costly rocket ammunition).

Regrettably, Zhao Shi Zhen's invention failed to catch the attention of Ming government, and never went beyond prototype stage.