A repeating crossbow is a crossbow where the separate actions of stringing the bow, placing the bolt and shooting it can be accomplished with a simple one-handed movement while keeping the crossbow stationary. This allows a higher rate of fire than a normal crossbow: there is a magazine containing a number of bolts on top of the bow, and the mechanism is worked by moving a rectangular lever forward and backward. Archaeological evidence of the earliest repeating crossbow was discovered in a Chinese tomb dated to the 4th century BC, during the Spring and Autumn period. The design for a repeating ballista is described in the works of the Greek engineer Philon of Byzantium, and is credited to Dionysius of Alexandria during the 3rd century BC. This device, known as the Polybolos, worked with a chain drive instead.
The Chinese repeating crossbow (Chinese: 諸葛弩; pinyin: zhūgě nǔ; Wade–Giles: chu-ke nu; literally "Zhuge crossbow"; sometimes romanized as "chu-ko-nu") is a device with a simple design. The bow string consisted of animal sinew twisted into a cord of suitable strength. Also known as the lián nǔ (simplified Chinese: 连弩; traditional Chinese: 連弩; literally "continuous crossbow"), the invention is commonly attributed to the strategist Zhuge Liang (181–234 AD) of the Three Kingdoms period, but those found in Tomb 47 at Qinjiazui, Hubei Province have been dated to the 4th century BC. Zhuge Liang improved the design of the repeating crossbow, and made a version which shot two to three bolts at once and was used in massed formations. For this reason, it was named after him. Other repeating crossbows fired as many as 10 bolts before exhausting the magazine. The bolts of one magazine are fired and reloaded by simply pushing and pulling the lever back and forth. Such action could fire 10 bolts in 15 seconds, after which the magazine would be reloaded. The weapon used by the ancient militaries was developed into a composite-recurve variety for more power. The recurved repeating crossbow is generally still weaker than the regular recurved crossbow, and was mainly used for sieges or behind shield cover. The Chinese repeating crossbow had a maximum range of 120 meters, with an effective range of 60 meters, far less than that of a non-repeating crossbow. Non-recurved versions of the repeating crossbow were often used for home defense. The repeating crossbow saw its last serious action as late as the China-Japan war of 1894–1895, where photographs show repeating crossbows as common weapons among Qing Dynasty troops. The basic construction of this weapon has remained very much unchanged since its invention, making it one of the longest-lived mechanical weapons.
The repeating crossbow was introduced into Korea by King Sejong (1418–1450), who during a trip to China saw the weapon and was impressed by its mechanism. In Korean it was called sunogung (Hangul: 수노궁; Hanja: 手弩弓).
A more complex repeating ballista was described in the works of the Greek engineer Philon of Byzantium. This siege engine was called a Polybolos and was reputedly invented by Dionysius of Alexandria in the 3rd century BC. Two flat-linked chains were connected to a windlass, which by winding back and forth would automatically fire the machine's arrows until its magazine was empty. The machine features the earliest recorded chain drive in the history of technology. The Chinese Repeating Crossbow was weaker in draw strength compared to other crossbows, so the arrows were often dipped in poison to cause death from even mild wounds.
The bow-string consisted of animal sinew twisted into a cord of suitable strength.
The small and light arrow of the comparatively weak Chinese crossbow had little penetrative power. For this reason the head of the arrow was sometimes dipped in poison, in order that a slight wound might prove fatal.
- Lin, Yun. "History of the Crossbow," in Chinese Classics & Culture, 1993, No. 4: p. 33–37.
- Werner Soedel, Vernard Foley: Ancient Catapults, Scientific American, Vol. 240, No. 3 (March 1979), pp. 124–125.
- "쇠뇌 1.수노궁". 조선의 무기와 갑옷 (in Korean). 2004. p. 98. ISBN 89-8435-207-1.
- Pyne-Gallwey, Sir Ralph: "The Crossbow". The Holland Press, Ninth Impression, 1990: p. 337.
- Crossbow Plans – How to build a repeating crossbow.
- CHU-KO-NU – The Chinese Repeating Crossbow
- The Chinese Repeating Crossbow From Ralph Frankland-Payne-Gallwey's work
- A highlight of the World Traditional Archery Festival in Korea was a demonstration of the Chinese repeating crossbow.