A Brief History of Japanese Armor

At Japanese History and Culture, there was an article that gave a brief history of Japanese Armor. Below is an excerpt. The full article may be read here.

The earliest Japanese armour were solid metal cuirasses made up of several sections of plate — often roughly triangular in form — which were tightly laced together and usually lacquered against rust. It is not clear what they were originally called; some suggest the term kawara — which means “tile” — and others suggest it was simply yoroi, meaning “armour.” This style of armour has come to be called a tankô, which means “short armour.” It was hinged on one side or even hingeless and sprung closed, opening up the center front. The heyday of the tankô was the fourth through sixth centuries. Various additions came and went, including lame-constructed skirt plates and shoulder guards.

The tankô was slowly phased out and replaced by a new form of armour which seems to have been inspired by continental models. This new form of armour eclipsed the tankô and set the pattern for the next millennium. The construction was of scale. Since the solid tankô rested on the hips and the new scale armour hung from the shoulders, the historiographical term given to these armours is keikô (“hanging armour”).

The general silhouette is hourglass-shaped. Keikô usually opened up the front, but models resembling ponchos were also known. Despite its early date (sixth through ninth centuries), the keikô was actually a more complex armour than later models, as there could be as many as six or more different types and sizes of scales used in one armour.

Most of what we know about the actual appearance and construction of tankô and keikô is due to the considerable efforts of the late Professor Suenaga Masao, an eminent archaeologist and historian, who painstakingly replicated dozens of different suits of armours after studying the remains excavated from Japanese mound tombs.

The introduction of Buddhism to Japan in the sixth century led to a phase-out of the old burial traditions and the subsequent loss of a great deal of archaeological material. From the last tombs of the eighth and ninth centuries until the oldest extant armour of the eleventh, we have a gap in which we can only surmise — based on what came before and what followed — the forms of armour worn in Japan. One form of keikô, the uchikake-shiki keikô, was clearly the last development of the keikô, and an obvious precursor to the next form of armour.

The Early Middle Ages

The classic Japanese armour, the heavy, square, boxy suit, is now called ô-yoroi (“great armour”) although it was originally just called yoroi. The oldest extant ô-yoroi is today just boards made of scales laced together. In other words, it is no longer a solid, wearable piece of armour. We can still tell what it is, and from the wisps of lace remaining in all the suspensory holes, we can also tell that it was a very ornate armour, with six different colors of lacing in a pyramidal pattern. The armour, now in Ôyamazumi Jinja, was made in the first two decades of the tenth century. This armour shows one last remnant of keikô construction: the lacing ran straight down in vertical lines. This vertical lacing also appears in a miniature armourer’s model of an ô-yoroi now in the Imperial collection. Armours of only a few decades later developed the down, diagonal, and up again lacing pattern now regarded as standard.

A significant feature of the ô-yoroi is that in cross-section viewed from above, the body forms a letter C, as it is completely open on the right side. Three large, heavy sets of skirt plates of kozane boards hang from it — one in front, one in back, and one on the left. The right side is protected by a solid metal plate called a waidate, from which hangs the fourth set of skirt plates. Two large square or rectangular shoulder protectors called ô-sode that were the size of LP album covers (remember those?) are attached at the shoulder straps. Small rounded flanges stick up from the shoulder straps to give added protection to the side of the neck.

Hanging in the front of the armour and ostensibly protecting the armpits that way were two plates called the sendan-no-ita and kyûbi-no-ita. The sendan resembles a miniature sode, and is worn on the right; the kyûbi is a solid plate, long and narrow, and worn on the left. These are both tied to the shoulder straps at the front of the suit.

Earliest ô-yoroi apparently had one fewer row of lames in the front and back of the skirt-plates; no doubt making them more comfortable when riding. Later models, starting around the twelfth century, had a full complement of skirt-plates, but the bottom-most lame in both the front and back was split in the middle to afford the same comfort.

Around the fourteenth century, an armpit plate was added to the left side. Previously, a strip of leather was just folded over the scale heads under the arm, but now a solid plate similar in shape to the munaita (“breastboard”) was laced into place. This served both to give added protection under the armpit and to lend strength to that part of the armour.

The second lame on the back, instead of being laced in the normal manner, is laced“inside out” — that is, the lacing for the next plate emerges from behind it rather than in front, so that it overlaps both the plate above and below instead of just the one above. Central on this plate, aptly called the sakaita (”reversed plate”), is a large, ornate fitting with a ring. This ring is the agemaki-no-kan, from which hangs a huge butterfly-shaped knot (agemaki). Cords coming from the rear of the sode are attached to the“wings” of this knot to help anchor the sode in place.

The entire front of the torso is covered with a printed or patterned leather apron called tsurubashiri (”bowstring-running”). The purpose of this covering is to keep the bowstring from catching on the heads of any of the scales as the warrior fired his primary weapon. Since armoured samurai often shot arrows with their hand along the breast rather than by their ear as was normal (the large helmets typically prevented usual firing methods), this was a logical development. This same leather pattern is used all over the armour: on the shoulder straps, the breast-board, the helmet turnbacks, the sode tops, the visor, etc.

Earliest warriors only wore one armoured sleeve (kote), and that on the left arm. The sleeve’s primary purpose was to keep the bulky armour-robe sleeves out of the way of the bow, however, not for protection per se. It wasn’t until the thirteenth century or so that matching pairs of armoured sleeves came to be common. The kote was donned before the armour, and tied across the body with long leather straps. The next piece worn was the separate side plate for the right side (waidate). Warriors typically wore these two items, the throat guard (nodowa) and their armoured greaves (suneate) around camp as a sort of “half-dress” armour. These items together are referred to as “kogusoku” or“small armour.”

The ô-yoroi is obviously a bulky and heavy armour. It was also expensive. For retainers and lesser warriors, the dô maru and haramaki were developed. These armours had more skirt plates and fitted closer to the body, omitting the need for a waidate. The dô-maru opens under the right arm; the haramaki opens at the back.