Repeating Crossbow
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Basic Information

A repeating crossbow is a crossbow that can fire multiple bolts or quarrels in rapid succession, without lengthy reload time between each shot. A few versions have been created over the years, with the best known being the Zhuge Nu.

Zhuge Nu

The Zhuge Nu (often Westernized as Chu Ko Nu) is a Chinese repeating crossbow that dates back to the 4th Century BC. It holds 7 to 10 crossbow bolts in a box-like magazine structure above the bow, which can be fired one at a time in rapid succession, emptying the entire weapon in as little as 15 seconds. It was fired from the hip, by pushing and pulling a lever back and forth or up and down, and had no "trigger" in the modern sense. It was not particularly accurate or penetrating. The main advantage of the weapon was its high rate of fire. Poison was commonly employed on the Zhuge Nu ammunition so that even a glancing strike to a limb would be likely to prove lethal.

The Zhuge Nu was essentially the 4th Century equivalent of the submachine gun. As with the modern weapons it parallels, the relatively short range of the Zhuge Nu makes it less than optimal for battles in the field. The Zhuge Nu user needed to avoid situations where the enemy would be able to stay out of your range and return fire from a distance with traditional crossbows or longbows. Where the Zhuge Nu did excel was in defending against siege, especially once the invaders had breached the wall. The high rate of fire could make it extremely dangerous for the enemy to rush a particular hallway, gate, or hole in the defenses. A small team of warriors armed with Zhuge Nu could hold a chokepoint by alternating their bursts and reloading times to keep up a steady stream of suppressive fire.

It is believed a double-barreled variant (or other multi-barreled weapon of similar purpose and design) existed as well. These double- and triple-bolt versions were occasionally used in massed formations on the battlefield, but the practice (and the physical weapons themselves) did not survive the centuries since their invention. One can assume that a weapon firing twice as many bolts as the Zhuge Nu would have been devastating up-close, but would fall to enemies with superior range or mobility.

Though an ancient weapon, the Zhuge Nu saw some battlefield use as recently as the First Sino-Japanese War in 1894 where many troops of the Qing Dynasty were armed with it.


The polybolos is a heavy repeating crossbow (bordering on ballista) invented by Dionysius of Alexandria in the 3rd Century BC. Its magazine holds dozens of bolts, and can keep up a steady rate of fire. It is operated by the cranking of an integral windlass, which may or may not conjure mental images of the revolving crank used to fire a gatling gun.

Since it is not meant to be man-portable, it can be made with greater draw-strength and thus possibly avoid some of the range and penetration limitations of the Zhuge Nu.

The surviving polybolos design uses a flat-link chain, which doesn't otherwise appear in surviving historical record until its (re-)invention by Leonardo da Vinci in the 15th Century.

Modern Weapons

If you hunt around the internet a bit, you'll find all sorts of enterprising individuals making prototype repeating crossbows. Some are based on the old Chinese or Greek designs, but others are battery powered or use re-purposed parts from a lawnmower. There's some crazy stuff out there.


1. Grand Historian dot com on the Zhuge Nu
2. Wikipedia on Repeating Crossbows in general, but mostly about the Zhuge Nu
3. Wikipedia on the Polybolos
4. YouTube video presentation on the polybolos with pictures. If you click on the "show more" button below the video, it has links to several other videos and sites with further information on crossbow-related topics.

Game and Story Use

  • Time-travelers and cocky PCs alike won't be expecting what is essentially the machine gun of the ancient world. You can use this weapon and its surprisingly high rate of fire to suddenly change the "rules" of the first battle they appear in, and overturn expectations.
    • It should be noted that a portion of the suppressive effects of modern firearms lies in the psychological effect of the noise of the weapon. If your game already has rules for suppression fire, you might penalize or limit the effectiveness of a repeating crossbow, at least relative to an actual machinegun. Ironically, while the lower noise level of a crossbow will reduce the psychological impact, it might make figuring out what's happening that much harder and thus increase the devastation of a surprise attack.
  • Speaking of time-travel, the Repeating Crossbow seems like just the thing a Connecticut Yankee might introduce to the era they were marooned in. It has the feel of an out-of-place artifact, so maybe it was invented by someone from the future!
  • Repeating Crossbows are a great weapon for shock troops, siege defenders, special forces, and the like. They aren't likely to be the mainstay of an army, but will excel in specific tactical situations.
    • Chances are the troops armed with the Zhuge Nu won't have the same level of training as the regular rank-and-file, and thus won't have the same stats. Depending on the nature of the setting, they may be elite troops taught to utilize special tactics, or they could be desperate civilians pressed into service and armed with an inaccurate weapon that requires no training.
  • Castle or fortress architecture could be built to specifically utilize the repeating crossbow. Firing stations could cover all the most likely entrances, and have fall-back positions for once the enemy has breached the outer defenses. In such circumstances, the weapons advantages would be even more deadly.
  • Unusual weapons are a fun form of treasure, or can be used to make a character stand out from all the other warrior-types.
    • I know most mad-scientists usually have death rays and the like, but some sort of crazy automated crossbow would be totally cool and flavorful. Just the sort of thing that someone with too much spare time and an understanding of basic engineering principles might build for fun. For a low-level, historical, or less cinematic game, this could work.
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