Shudo (手弩) and Ōyumi (大弓) - Japanese Crossbows

Shudo (手弩) and Ōyumi (大弓) - Japanese Crossbows

Ono no Harukaze using a crossbow, from 前賢故実.

In this article I would like to address one of the most mysterious and interesting aspect of Japanese military history: Crossbow's usage.
In fact, people usually (and for a very good number of reasons which I will explain in this article) don't associate Japan with crossbows at all.
However, not only the Japanese knew crossbows, they also occasionally used them in warfare.

First, it is fair to point out that unlike other unknown elements of ancient and feudal Japanese warfare, like shields, axes or maces which are usually not associated neither with Japan or the Samurai, the crossbow never saw much use at all.
If those aforementioned weapons were rare, the crossbow was even more rare; but it is still worth talk about it.

Shudo (手弩) - Hand held crossbow
Shudo is the Japanese name for hand held crossbows, but it is not the only one. It was also know as ishiyumi ( written either 弩 or 石弓), shudo (手弩), doshu (弩手) or dokyū (弩弓).

The first type of crossbow found in Japan was excavated in Shimane prefecture and dates back to the Yayoi period (probably around the 200-300 A.D). Like anything dealing with Yayoi, not much is known and that is the only example excavated.
It was a rather simple model, made of wood.

There are other references for this kind of weapon; the first is inside a report concerning a bandit raid on the Dewa provincial office in 878, in which “100 shudo" were stolen. The second, an inventory from the Kōzuke provincial office compiled around 1030, lists “25 shudo” (apparently its entire stock) as missing.
According to design and the manufacture of the only trigger mechanism excavated in Japan, which was made of bronze, these crossbows were imported from China or Korea.
We do not know how they looked like nor how powerful they were, unfortunately.
It is possible that crossbows saw relative use in between the 9th and 10th century, but the few scattered evidences disappeared completely from Japan after this period, up until the Edo jidai.

A sketch of a shudo from 請求記号, Edo period.

There are few examples of crossbows from the Tokugawa age; some are inside private collections, others are preserved in the Royal Armories museum in Leeds and at the MET.
These late shudo are made with whale bones and they are built in two layers like leaf-spring.
The one at the Met, at least from its description, was made with horn, steel and wood.It is very possible that these crossbows were either based on Chinese models, or directly imported.
The ones in the R.A. museum has still its own bolts, which are fitted with armor piercing heads.

A Japanese crossbow's bolt from the Met museum.

Although these weapons look functional, it is impossible to establish the power or if they were made to work as weapons and not as toys for the bored Samurai of the Edo period. Just like with their 9th and 10th centuries counterparts, we do not know much about them.

Another hand held crossbow worth mentioning is the steel crossbow ordered by Matsudaira Sadanobu in the early 19th century. It was made in 1820, and the design is quite impressive considering the fact that Japan stayed with Sengoku period technology up until the mid 19th century.
The bow was made of spring tempered steel, and the trigger mechanism itself had a spring made of steel.
As I have already explained in my article about bow, the Japanese were already familiar with steel bows (and thus spring tempering) at least since the 16th century, although they were rare due to the cost and practical issues of producing and using a bow of steel.

                                                                             

The first part of the crossbow, with the bow and part of stock

The second part of the crossbow, with the stock and other components.

The entire weapon drawn

So, why were these weapons not considered that much in Japan, especially during the Samurai warfare age? It may look odd, considering the distance from China, a country that made crossbows one of their military symbols for much of their history.
There are a good number of reasons which explain the situation quite well.

The first reason has to do with native production issues. To make an efficient crossbow capable of piercing armor, you need either spring tempered steel or a composite structure made of horn, bones, sinews and wood, which was the way early crossbows were made pretty much everywhere.
The problem with tempering steel is that the technology required to make a homogeneous piece of steel and then properly hardening and tempering it wasn't available prior to the 10th (century and even later), not to mention the cost of such products.

On the other hand, as I have explained in my article about Japanese bows, Japan lacked any serious supply of bones, horns and sinews.
This wasn't a major problem with bow construction, since you could still make a very powerful bow with wood and bamboo; it only need to be very long, hence the dimension of the Yumi.
However, this is a major drawback with crossbows design; manufacturing crossbows with composite bow staves of wood and bamboo comparable in length to those of regular bows would have resulted in a weapon too unwieldy to be practical: not merely extraordinarily wide – and not readily usable by troops standing in close ranks – but also extraordinarily long, as it would have been necessary to lengthen the stock to permit a sufficient draw.    

This however wasn't the only problem. In fact, importing Chinese models would have solved the issue, and as far as we know the few crossbows used prior to the 10th century were indeed imported from China.
There was a true indifference to this weapon in Japan, mainly due to its tactical limitations.

While crossbows are extremely effective weapons, they have some detrimental flaws that made them unsuitable for the Japanese warfare of the period.
Crossbows cannot be reloaded while riding a horse, or while walking, they need drilling and serious training to be operated properly, they are cumbersome to carry around and their "rate of fire" is very slow compared to that of bows.

The military structure and organization of the early Samurai didn't allow these weapons to prosper, because of the lack of discipline among infantry soldiers, the prevalence of mounted warriors  as well as the very mountainous and uneven terrain of Japan. All these aspects combined made hand held crossbows a bad choice for the typical Japanese medieval warrior, and soon the bow prevailed up until the mid 16th century. 

Ōyumi (大弓) - Siege crossbow

While hand held crossbows saw limited use throughout the entire military history of Japan, the same cannot be said about siege crossbows, called Ōyumi. This weapon is a little bit more famous and there are more sources that deal with it.However, just like the other crossbows, we do not know how it looked like nor how it was supposed to work. Descriptions or drawings have never been found.

It appears to have been some sort of platform-mounted, crossbow-style catapult, on the order of the Greek oxybeles or lithobolos, the Roman ballista, and similar devices, perhaps capable of launching volleys of arrows or stones in a single shooting, possibly a variation of the Chinese repeating crossbow.

A possible artistic representation of the Ōyumi.

This artillery weapon was brought to Japan by Koreans in 618 and the Japanese started to deploying it regularly by the 670s against the Emishi.

A chronicle entry from 835 notes the existence of a “new ōyumi” (shindo), invented by

Shimagi Fubito Makoto, that was supposed to have been able to rotate freely, shoot in all directions, and be easier to discharge than the existing design. The text remarks that, when the weapon was demonstrated, the assembled courtiers could “hear the sound of it being set off, but could not see even the shadows of the arrows as they passed."
Siege crossbows were placed on several key locations on the Sea of Japan to prevent a Silla pirates raids during the 9th century.

One critical limit of this weapon was the skill required to use it. Several sources underlined how hard it was to operate it and that troops needed to be trained to use it.

Between 814 and 901, the court received requests for ōyumi instructors from no fewer than seventeen provinces. All had the same complaint: regrettably, the weapons in their armories were going to waste because no one knew how to use them.

Despite this limit and the slow decline, siege crossbows were still used up until the late 12th century.
In the Mutsu Waki, describing the war of the 1053 to the 1062, the use of both arrows and stones is recorded.
The usage of the ōyumi is also recorded in the Gosannen Kassen Ekotoba dealing with the war of the late 11th century and the last recorded use is dated to the 12th century, during the Gempei war.
The skill required to use and make such weapon declined through the ages, so it is not a surprise to see this weapon disappearing completely after the 12th century, when a long period of peace was established and the knowledge behind the ōyumi was lost forever.

I Hope that you liked the article, for any question, don't hesitate to write a comment! I'll be glad to answer.
Feel free to share the article and spread the word! Thank you so much for your time.

Gunbai