Japanese Armor Weight

Japanese Armor Weight 

When it comes to armor, of any type, the questions that came into mind are usually these ones:
How much does it protect you, how much does it restrict your movement and finally;
How much does it weigh?


Today I would love to answer this latest question, talking mainly about two style of Japanese armor; the classical "O'Yoroi" and the modern "Tosei Gusoku" with the associated auxiliary pieces.

Okegawa dou (桶側胴 ) from 甲冑名所図

An Oyoroi (大鎧) from 甲冑備考

( I would have love to add something more regarding the style of early DouMaru & Haramaki - 胴丸&腹巻, but the lack of any decent data was disturbing, so they would be only mentioned with some estimations).

DISCLAIMER: The data found on this post were collected through museum collections, private collections & auction houses and therefore subjected to possible errors. The estimations are mine ( an amateur researcher which some logic behind his writings) and are only a small amount of data, but they are far from being scientific or correct. Take this information with the proper care.

O'YOROI

For more information on this type of armor, you could read this article here; in this section I will only talk about its weight and weight distribution.
As far as this suit is concerned, there are plenty of sources talking about its heaviness; on a general statement I would agree, however there are some corrections I have to add on the topic.
The majority of people says that a full suit of this type from the 12th century onward ( which means an helmet, the torso, a pair of shield-sleeve, a pair of armored sleeve, armored mask and greaves) is about 30 kilograms or even more.

Two warriors wearing Oyoroi style of armor, print made by Tsukioka Yoshitoshi (月岡 芳年)

I have only few examples to counter this assumption due to the amount of data available on the internet, but at least to me it seems that the range of weight was closer to the 25-26 kilograms  rather than the 30 kilograms ( yet is also true that with weapons and other gears the weight might reach 30 kilograms).

Some years ago the famous Akai itou odoshi yoroi (赤絲威鎧)  was weighed and it turns out the be 22,6 kg:


兜:　　    3,8 kg   (Helmet - Kabuto)
胴:　　   13,5 kg  (Torso - Dou)
脇楯:　　2,4 kg   (Side plate - Waidate)
袖:　　    2,2 kg   (Shield sleeve - OSode)
栴檀板:　0,5 kg   (Additional lamellar plate - Sedan no ita)
鳩尾板:　0,3 kg   (Additional solid plate - Kyubi no ita)


However it is fair to notice that this specific armor dating from the 12th century is devoid of an Happuri - 半首 ( armored mask ), a pair of greaves (Suneate - 臑当 ) and armored sleeves ( Kote - 籠手) which would increase the weight from 22,6 to approximately 26-26,5 kg*. If you add the quiver, the sword and the bow the 30kg spot seems legit, but the armor is actually less heavier on its own.

The armor mentioned above before the restoration - 12th century

Another similar type of armor inside the Met Museum collection was weighed and it turns out to be 17,3 kilograms; compared with the other suit it was devoid of the Osode, Happuri, Kote and Suneate.
However the weight of the others component are similar:

兜:  5,53 kg

胴 + 脇楯 + 栴檀板 + 鳩尾板 : 11,77 kg

And if we add on the harness all the other pieces ( technically called Kogusoku - 小具足) we could reach the same 25-26 kilograms (and not 30 kg if you will )

The O'yoroi of the Met museum, early 14th Century 

On the Royal Armouries of Leeds there is a genuine "modern" replica with some individual measurement;

兜: 6,0 kg (with decorative Kuwagata - 鍬形 horns)
袖: 2,5 kg
栴檀板: 0,625 kg
鳩尾板: 0, 340 kg


Again, the weight of individual components are quite similar with the other measurements.

It might be surprising to see a complete O'yoroi being in the 25-26 kg range when seeing the amount of protection that could offer, but you have to think that the suit was made with iron, leather & silk and a lot of overlapping; every piece of material adds some weight.
Of course is still worth notice that any single armor is unique and trying to generalize is a bit misleading. Some armors were entirely made with Kneaded Leather - Nerigawa (練革) and thus they were lighter, others were made with a triple overlapping lamellae structure called Mitsume Zane and so much more heavier.

It is fair to understand that 26-30 kilograms of armor are not that "heavy": some field&tilt harness worn in Europe could reach 38 kg (  BUT these types of armors were rare exception!)

But when judging the weight of a suit of armor, we also have  to consider the weight distribution, namely where the weigh is resting on the body:

If the majority of weight is resting on the shoulders, even a small amount of burden would be harder to carry, and if is up to 20 kilograms it would be difficult to be involved in a fight for long periods.
If the weight instead is resting on the hips, it is easier carrying it, more comfortable and it won't be a problem in a fight.

The O'yoroi weight rested on the shoulders, and so it is uncomfortable on longer period and awkward to wear on foot; and this is why this kind of armor is considered and horseman armor.
In fact the O'yoroi was designed to be worn on horseback, so that the weigh partially shifted from the shoulders of the wearer to the saddle of the horse; in addition to that, the warrior could benefit of an higher mobility without consuming the energy for walking or running.

Notes: * the estimation was based on data concerning the Kote and the Suneate of the modern period - not too dissimilar to the ones used in the time frame considered

Warriors wearing Oyoroi - detail from the 平治物語絵巻

While considering the Dou Maru & Haramaki style of armor, the weight of the Dou decreased a lot; there was no Waidate ( side plate), it was shorter, and since the shape wasn't boxy like the Oyoroi but more rounded, there were less lamellae.
So it seems that the weight of these types of Dou was around 4-6 kg instead of the 11-13 kg of the Oyoroi's Dou, so more or less 10 to 8 kg lighter. This dropped the total weight of the armor under 20 kg, even if we add armor pieces like the Haidate.

In addition to that, the weight could be divided between shoulders and hips by tying a belt or a sash on the waist ( a similar technique was used with mail armor).

Dou Maru and Haramaki from 軍用記

TOSEI GUSOKU

When it comes to the so called Modern Armor - Tosei Gusoku (当世具足), the armor originated in the late 15th century, I was able to collect the data from various sources (from museum, auction houses and private collector) since its incredible popularity (and quantity).
But is not as easy as it was with the Oyoroi to identify this type of armor: there are a lot of different styles, armored pieces which could be worn or not and a lot of variations in thicknesses and material used.
So I've decided to give some raw data and then have a little discussion.

Portrait of Satake Yoshinobu (佐竹 義宣) wearing a typical Tosei Gusoku Armor

First of all, the "weight distribution";
Tosei Gusoku armor are almost always Tachi dou (立胴) armor, which roughly means "standing armor"; in fact, either made of plates or lamellae they are usually hinged on one or more sides so they don't collapse because they are "rigid". Due to this feature, the weight rested on the hips rather than on the shoulders.  This weight distribution was already in use in the 15th century when the scales or lamellae were warped in a slight S-shape to force the upper row under the row below it, and with the aid of a sash or a belt tied at the waist.
So they are more comfortable and effective than their predecessor, either on foot and on horseback.

For a complete set of this style of armor we have:

Arming Garments (満智羅 - Manchira), Helmet (兜 - Kabuto), Armored mask with a "Gorget" (面具 + 垂 - Mengu + Tare ), a Breastplate with Backplates and Tassets (胴 + 下散 - Dou + Gessan), Pauldrons (袖 - Sode), Armored sleeves with Gauntlet  (籠手 + 手甲 - Kote + Tekou), Cuisses (佩楯 - Haidate), Greaves (臑当 - Suneate) and Sabatons (甲懸 - Kogake).

Helmet (17 samples):
Min: 1,3 kg
Max: 4,3 kg

Average: 2,12 kg

Armored mask with Gorget (10 samples):
Min: 0,280 kg
Max: 0,605 kg
Average: 0,423 kg

Brestplate with backplate and tassets (20 samples):
Min: 3,4 kg
Max: 11 kg
Average: 5,69 kg

Armored Sleeves and Gauntlets (pair) (16 samples):
Min: 1,01 kg
Max: 4,59 kg
Average: 1,84 kg

Pauldrons (15 samples):
Min: 0,650 kg
Max: 1,45 kg
Average: 1,2 kg

Cuisses (13 samples):
Min: 0,4 kg
Max: 2,85 kg
Average: 1,07 kg

Greaves (pair) (11 samples):
Min: 0,635 kg
Max: 1,5 kg
Average: 1,08 kg

Arming Garments (3 samples):
Min: 1 kg
Max: 2,99 kg
Average: Only two available,  1,78 kg

Sabaton (pair):
Only one available: 0,700 kg

Complete suit ** (24 samples):
Min: 8,75 kg
Max: 27 kg
Average: 16,02 kg

Average of main components added: 16,11 kg (which is pretty close to the average of complete suits )

Notes: ** I've considered "Complete suit" armors which were at least fitted with Helmet, Breastplates, Cuisses, Armored Sleeves and Greaves. The majority also have Armored mask and 

Pauldrons, very few Sabatons too. Most of the armors were in between the 13-17 kg range. 

Yamanaka Yukimori (山中 幸盛) wearing a type of Tosei Gusoku armor, print by Yoshitoshi

As I mentioned before, every suit of armor is unique and there are a lot of variations in between styles; is quite obvious that the more protective gears are also the heaviest: a complete harness like the one used by the retainers was likely to be in the 10 kg spot, while an high end example worn by a mounted warrior was more in the 20-22 kg spot. The average wealthy samurai would have worn more or less 14-16 kg of armor.

Materials and thicknesses play a major role here:
For example a Tameshi Kabuto which is bulletproof would have been more than 2 kg, while a Dou with the Gessan (or Kusazuri - 草摺) of kneaded leather (nerigawa) would have been around 4 kg.
Same for the Pauldrons and the Cuisses; sometimes they were made of kneaded leather too and so less than 0,6 kg & 0,8 kg respectively.
If the metal's thicknesses was around 1mm or even less, the total weight would have been closer to the 10 kg spot, while being more than 2mm, it would have been closer to the 20kg spot.

However when it comes to Tosei Gusoku, a full suit rarely exceed the 22-25 kg and often is below the 20 kg (based on my amateur research/measurements/estimations, so totally unscientific but at least closer to some degree to what might have been the reality.)
Yet is fair to notice that some Tameshi Gusoku, thick, with a lot of armored zones and few "gaps" existed side by side of some entire Nerigawa Gusoku, which were much more lighter (and thus less protective).