Chinese multiprod crossbow

MINOR UPDATE OCTOBER 2, 2024

Credited with the invention of crossbow, the Chinese were keen on tinkering with their crossbow and coming out with ever more efficient and powerful designs. Apart from repeating crossbow, which was invented as early as 4th century BC, Chinese bowyers also created another unique crossbow design—the multiprod crossbow, sometimes also known as multiple bow arcuballista. The weapon mounted multiple prods to extend the draw length (and powerstroke) of the crossbow, thus getting more power out of the same draw weight. It was also more efficient and portable than a single prod crossbow of equal power.

There were several variants of multiprod crossbow in use during Tang and Song period, which will be detailed below:

Shuang Gong Chuan Nu (雙弓床弩, lit. 'Double-prod bed crossbow')

Also known as Liang Gong Nu (兩弓弩, lit. 'Two prod crossbow') during Tang period, this crossbow had two prods mounted facing opposite directions of each other. It was spanned by a simple windlass.

Da He Chan Nu (大合蟬弩, lit. 'Great combined cicada crossbow')

Drawing of a Da He Chan Nu, from 'Wu Bei Zhi (《武備志》)'.

So named because the prod configuration gave off the impression of a pair of mating cicadas, He Chan Nu (合蟬弩, lit. 'Combined cicada crossbow') was simply another name of double-prod crossbow. Da He Chan Nu was the larger version of double-prod crossbow that required seven to ten men to span. It had a range of about one hundred and fifty paces.

*NOTE: A Song Dynasty pace can be roughly equated to 1.536 metre or 1.68 yard.

Xiao He Chan Nu (小合蟬弩, lit. 'Small combined cicada crossbow')

Drawing of a Xiao He Chan Nu, from 'Wu Bei Zhi (《武備志》)'.

Xiao He Chan Nu was the smaller version of He Chan Nu. It required five to seven men to span, and had a range of about one hundred and forty paces.

San Gong Chuang Nu (三弓床弩, lit. 'Three prod bed crossbow')

Also known as Ba Niu Nu (八牛弩, lit. 'Eight ox crossbow'), this crossbow mounted three prods, with two prod facing forward and one prod facing backward. It was significantly more powerful than its double-prod counterpart.

It is speculated that Kaman-i Gav (lit. 'Ox bow') used by the Mongols during the siege of the Hashashin castle of Maymum Diz in 1256 was in fact a San Gong Chuang Nu.

San Gong Nu (三弓弩, lit. 'Three prod crossbow')

Drawing of a San Gong Nu, from 'Wu Bei Zhi (《武備志》)'.

San Gong Nu was the ubiquitous Chinese triple-prod siege crossbow. Extremely powerful, it required seventy to more than one hundred men to span, and had a range of three hundred paces (although its maximum range may well exceed one thousand paces).

Ci San Gong Nu (次三弓弩, lit. 'Lesser three prod crossbow')

Drawing of a Ci San Gong Nu, from 'Wu Bei Zhi (《武備志》)'.

Ci San Gong Nu was a smaller version of San Gong Nu. It required only thirty to seventy men to span, and had a range of about two hundred paces. While less powerful than its larger counterpart, Ci San Gong Nu was still extremely powerful for its size, not to mention its portability made it uniquely suited for siege situation, where it could be used to shoot specialised arrows designed to bury deep into the wall to be used by attacking troops as climbing steps.

Dou Zi Nu (㪷子弩, lit. 'Bucket crossbow')

Dou Zi Nu was a modified multiprod crossbow with an iron bucket tied to its string. Instead of shooting a single large crossbow bolt, Dou Zi Nu shot dozens of normal-sized arrows from its iron bucket over a large area.

Presumably, all multiprod crossbows could be converted into Dou Zi Nu.

Dou Zi Nu (㪷子弩)

Drawing of a Dou Zi Nu, from 'Wu Bei Zhi (《武備志》)'.

Dou Zi Nu required only four men to span. While weaker than even a Xiao He Chan Nu, it still had a range of about one hundred and fifty paces.

San Gong Dou Zi Nu (三弓㪷子弩)

Drawing of a San Gong Dou Zi Nu, from 'Wu Bei Zhi (《武備志》)'.

San Gong Dou Zi Nu was the triple-prod version of Dou Zi Nu. It had a range of about two hundred paces.

Shou She Nu (手射弩, lit. 'Hand-shot crossbow')

Due to the tremendous power conferred by having multiple prods, most multiprod crossbows had very robust trigger mechanisms and extremely high trigger weight, necessitating crossbow operators to knock the trigger forcefully with a wooden club to release the bolt, which was somewhat inconvenient to use. Shou She Nu was thus designed to be an easier-to-use version of multiprod crossbow, giving up some hitting power in exchange for a lighter, hand-operable trigger mechanism.

Shou She He Chan Nu (手射合蟬弩, lit. 'Hand-shot combined cicada crossbow')

Shou She He Chan Nu was the hand-triggered version of double-prod crossbow. Unfortunately, no other information is available for this crossbow.

Shou She Nu (手射弩)

Drawing of a Shou She Nu, from 'Wu Bei Zhi (《武備志》)'.

Presumably also called Shou She San Gong Nu (手射三弓弩, lit. 'Hand-shot three prod crossbow'), this was the hand-triggered version of triple-prod crossbow. It still required up to twenty men to span, and had a range of about one hundred and fifty paces.

Shou She Dou Zi Nu (手射㪷子弩, lit. 'Hand-shot bucket crossbow')

Shou She Dou Zi Nu was the handheld version of Dou Zi Nu and was described as the smallest of all multiprod crossbows. It required less than five men to span, but still retained a range of around one hundred and twenty paces.

Crossbow bolt

From left to right: Tie Yu Zao Tou Jian, Da Zao Tou Jian, Xiao Zao Tou Jian, Ta Jue Jian, Yi Qiang San Jian Jian, Dou Zi Jian. It should be reminded that these crossbow bolts are NOT properly scaled to each other.

Chinese multiprod crossbow could be loaded with a variety of crossbow bolts, each designed for different purposes.

Zao Tou Jian (鑿頭箭, lit. 'Chisel-headed arrow')

Like its namesake, Zao Tou Jian had a chisel-like arrowhead, presumably designed to inflict wide gaping wounds. The fletching of Zhao Tou Jian could be made of either iron or feathers.

Zao Tou Jian came in a variety of sizes, the smallest variant could apparently be loaded into the iron bucket of a small Dou Zi Nu.

Ta Jue Jian (踏撅箭, lit. 'Stepping arrow')

Ta Jue Jian was designed to be used as scaling step for besieging troops. As such, its had a large barbed arrowhead designed to pierce and lodge firmly into hard surfaces, as well as a thick and sturdy shaft that could withstand the force of impact and the weight of an armoured trooper.

With the power of multiprod crossbow behind it, this type of crossbow bolt could punch into stone brick.

Yi Qiang San Jian Jian (一鎗三劒箭, lit. 'One spear three swords arrow')

Yi Qiang San Jian Jian was the largest and most deadly of the multiprod crossbow bolts. Essentially a heavy spear with three iron fletches (the three "swords"), it was only launched from the largest San Gong Chuang Nu.

Dou Zi Jian (㪷子箭)

Dou Zi Jian did not refer to a specific type of arrow, but referred to the normal-sized arrows loaded inside the iron bucket of Dou Zi Nu. It was also known as Han Ya Jian (寒鴉箭, lit. 'Jackdaw arrow').

Black powder incendiary bolt

All of the aforementioned crossbow bolts could be tipped with incendiary or poison smoke warheads (or both) to further enhance their destructive potentials. A particular nasty version was the incendiary Dou Zi Jian that could set a wide area ablaze.

EXTRA: Just how powerful is Chinese multiprod crossbow?

Unfortunately, written records are silent on the matter of dimensions and precise draw weights of these siege weapons, so all estimations on the power of multiprod crossbow are merely educated guesses. That being said, all known multprod crossbow variants inevitably come with windlasses that require at least two operators, so they must be quite powerful.

Moreover, since none of the windlasses look like they can be used by more than four operators (let alone one hundred), records of "X number of men required to span the crossbow" must therefore refer to the number of men required to span the crossbow without using windlass, perhaps in a manner not too dissimilar to tug-of-war. Even under the most unfavourable assumption that one man can only pull a meagre 12 kilograms/22.5 pounds (in reality a physically fit and well-trained man can pull roughly twice his own weight), a large San Gong Nu spanned by one hundred men would still have a draw weight of roughly 2645 pounds!

Replica

China's CCTV-9 television channel created a full-scale replica of San Gong Chuang Nu for its ancient Chinese weapon documentary series. The replica manages an impressive 61 inches powerstroke, but only has a paltry draw weight of 390 pounds (incredibly underpowered for a weapon of this size). It can only shoot a spear-sized crossbow bolt (size and weight not given, but most likely too heavy for the draw weight) at an abysmal 91.8 fps.

A complete failure, regrettably.

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