Samurai Armor: Military Protection in Japan
Japan History

Research Report
Web Resources

Yoroi armor


        If there is one constant that ties together every country on earth, its war; and with war there comes the need for protection, in the form of armor and shields.  The armor of Japan was similar to the armor found in Europe in its earliest forms, but as it evolved with changing weapons and battle strategies, its look diverged from the more familiar armor of the west.  As it evolved, it became almost as important for a Japanese suit of armor to be beautiful as to be an effective means of defense.

Research Report

        The earliest forms of armor in Japan are unknown but they were probably not too different from primitive armor from other parts of the world.  The earliest examples that have been found on the island are from the Yamato Period, dating to between AD 300 and 600, called tanko.  Similar to early Roman armor, a tanko cuirass, the part that protects the torso, consisted of horizontally riveted plates that were built on a frame.  It was laced in the front with leather thongs, and fit tightly to the body.  Over this was worn a pair of metal plates that covered the shoulders and upper arms, and a two piece, hoop-like skirt of narrow iron plates, laced together with extra thickness towards the bottom to provide stiffness; the legs, however, remained unprotected.  The tanko helmet resembled a modern day baseball cap, with a stiff beak in the front and was made of small iron plates laced or riveted together to form a rounded dome.  From the back and sides of the helmet hung longer plates, laced together and laminated to protect the neck (Blair, 480-481).  This type of stiff, close fitting armor lent itself to foot soldiers, wielding swords and spears at close range.  It is believed that the armies of the early Yamato Emperors used tanko armor as they expanded their territory; an expansion that eventually brought them in contact with Korea.  Contact with the mainland meant a flood of new ideas flowing into Japan, including a new way of constructing armor (Yamagami, 10-11).
        The heavy Korean and Chinese influence was seen in the keiko, “hanging armor”(Samurai Warfare, 13). When horses were brought to Japan from the mainland, cavalrymen became more popular, and a new style of armor construction was brought in from Korea that was made from interlaced lamellae—thin, pliable strips of iron or steel. This lamellar construction resulted in a lighter, more flexible armor that was ideal for archers.  The Japanese adapted the lamellar technique, and made the keiko cuirass in a form similar to the tanko; it became a sleeveless jacket, laced in the front and held over the shoulders with cotton cords.  Like the tanko, the keiko was completed with neck and shoulder guards, and a stiff skirt that reached to mid-thigh.  The keiko helmet differed from the tanko one, as it lacked a stiff beak and had a flat top with holes from which could be stuck feathers or hair (Blair, 295).  With the new armor came the first horses to Japan, which quickly became popular as mounts for units of mounted bowmen.  The growth of the mounted bowman in Japanese battles led to the altering of the keiko armor, and the development of an entirely new kind.

         In the 8th century AD, the keiko grew larger, boxier and more elaborate, evolving into the yoroi (harness), sometimes called the oyoroi (great harness), and weighed over 30 kg (Samurai Warfare, 22).  During this period, Japanese armor also grew beyond its utilitarian roots as the samurai warrior class emerged.  The way a warrior’s armor looked became almost as important as how well it performed in battle.

The first requirement of armour was to be strong and fit for practical use.  Another notable point was that it must be beautiful, at least for the old Japanese…the life of warriors was guided not only by moral principles but also by a sensitiveness to beauty.  They had to win in battles above everything else, and therefore they respected military strength.  Yet the aesthetic side of their character was in harmony with their military life, though to some it may sound contradictory.  Therein lie the characteristics of Busido.  The warriors’ love of beautiful things and art was not sentimental or epicurean, but was an important factor through which they cultivated their personality and purified their life.  This thought is reflected in the armour and arms of the period (Yamagami, 14).
        Yoroi, like the earlier keiko, was a lamellar armor, built up of small plates of iron and/or cowhide and tied together with silk or leather lacing (The Samurai Sourcebook 95).  Improving on the keiko design, yoroi lamellae were coated with a lacquer that both strengthened it, and protected it from the moist climate of Japan.  In addition to lammelar elements, yoroi had some components of plate armor—iron, covered on both sides with leather (Blair, 507).

        The main part yoroi helmet, the kabuto, was a low, rounded bowl made of several riveted plates, and had a hole through which the samurai’s short pigtail could pass.  The neck was protected by the shikoro, which consisted of five lamellae laced horizontally.  To prevent the possibility of a sword thrust getting between the lamellae and cutting the cords that held them together, the shikoro was turned back on itself on either side of the face, forming two wing-like flaps that were covered with leather (Blair, 508).  Some warriors complimented the kabuto with the happuri, a black lacquered facemask that covered the forehead and the cheeks (The Samurai Sourcebook, 95).
a mounted samurai in yoroi
       The body was covered with a boxy cuirass called the do, which consisted of two main parts.  The waidate, which was a plate above and laminations below, protected the right side, and was placed under the right arm and tied onto the body before the rest of the armor.  The remaining part of the do was a 3-sided piece that covered the front, left side, and back; like the waidate, it was plate armor on top, and laminates below (Blair, 508).  The plate covering the front was made narrow, to allow the arms the movement needed to draw a bow back; in addition, the bottom part of the do, the lammelar section, was wider at the bottom, creating a pyramid-like skirt—necessary to accommodate leg movement while astride a horse (Yamagami, 16).  Two large plates, sode, protected the shoulders, and were fastened at the back by a large bow.  These sode were approximately 1ft x 1ft, and were able to move forward and backward with the samurai’s arm, acting as a shield against arrows and sword blows (Yamagami, 15).  The left arm was covered by an armored sleeve called the kote, while the right arm, used to draw back the bow, remained unprotected (Blair, 300).  The yoroi was too large and bulky to allow its wearer to fight with a sword on foot for long periods of time but it was ideal for the samurai warrior of the time, who fought almost exclusively with the bow from horseback.  Even so, it was restrictive enough that the warrior could only fire to his left, in an arc of about 45 degrees (Samurai Warfare, 24).  If anything, it was intimidating, and “a knight clad in such armor took on the appearance of a supernatural being” (Blair, 507).  However, the yoroi was reserved for the elite samurai warriors, the soldiers that they commanded and their attendants wore a simpler type of armor, called the do-maru.

        Unlike the large, boxy yoroi, the do-maru fit close to the body.  It was made of lamallae laced together with brightly colored silk cords (Blair, 168).  Laced on the right side, under the arm, and cinched at the waist, it looked like a sleeveless jacket.  Like the yoroi, it had large sode to protect the shoulders and an armored sleeve for the left arm; however, the skirt was made of six panels instead of four and lay flat against the upper legs.  Similar to the do-maru was the haramaki, which laced in the back instead of along the side.  These three types of armor remained in use through the end of the Ashikaga Period, changing very little, but around the time of the Onin War in the late 15th century, a noticeable change began to become apparent in the lighter do-maru armor (The Samurai Sourcebook, 96).

        It was at this time in Japan’s history that the bow began to be phased out as a weapon by the samurai in favor of the sword, which in turn led to the decline of the yoroi.  More and more samurai began to wear the do-maru, as much combat began to be done on foot, in wooded and hilly areas unsuitable for cavalry.  The switch in focus from the bow to the sword could be seen in several part of the armor; in addition to the new do, kote were now worn on both arms, and the armor Edo Period kabuto covering the thighs and calves became more developed (Samurai Warfare, 46-47).  As Japan was plunged into 100 years of fierce civil war in the Sengoku period, the armor of the foot soldiers began to evolve further.  First, the general shape of the do changed; instead of being supported entirely by the shoulders, like the yoroi, through the use of uniquely shaped and sized horizontal lamellae, it became supported by the hips and waist as well.  In addition, the symmetrical, close laced, small lames were replaced, in some cases, by larger plates and more spaced out lacing--a process that cut down on manufacturing time considerably.  During this period, there emerged dozens of different types of do-maru, each with slight differences in the way they were manufactured (The Samurai Sourcebook, 96).  Some of the more exotic variaties of do-maru employed riveted and lacquered plates to create bizarre looking torso armor, such as examples that resembled a gaunt, naked human body with sagging breasts visible ribs, or one with a bloated, protruding stomach (The Samurai Sourcebook, 102).  Some armorers even adopted the style of the armor of the newly arrived Europeans, discarding lammellar do in favor of much heavier solid steel plates for the breast and back (Blair 168). At this same time, the Europeans brought something else that would drastically affect combat in Japan—the firearm.  Soon after the Portuguese brought reliable gunpowder weapons to Japan, the Japanese were producing quality guns of their own.  A bullet fired from one of these early matchlock muskets could have a devastating effect on an armored warrior.  At 50 m, a bullet from one of these guns could pierce a 1mm thick iron plate and put a substantial dent in one 2 mm thick; as the typical do-maru armor was made of 0.8 mm thick iron plate, firearms soon became the trump card in most battles (Samurai Warfare, 76).  Oda Nobinaga and his successors in the latter half of the 16th century used the firearms to their advantage, unifying Japan’s warring daimyos and leading the country to the long period of peace known as the Edo Period.

Historical Significance

      The peace of the Edo Period was the beginning of the end for the samurai, who lived in a society that no longer needed them in their former warrior roles.  This, combined with the destructive power of firearms and artillery, put an end to the need for traditional armor in the context of war.  However, armor called gusoku was produced during this period; instead of being worn, gusoku were given as prestige gifts and displayed (The Samurai Sourcebook, 103). Gusoku armor encompassed a wide variety of shapes and styles: the appearance of some was highly influenced by European armor, and sometimes even incorporated pieces of it; others were reminiscent of the older yoroi, do-maru, and haramaki styles; and some even incoporated bits of chain mail to supliment traditional components.  More often than not, gusoku were more decorative than functional, and they became closer to works of art that tools of war.  Bizarre, intricate, and grotesque do were produced in this period, including ones with eyes over the nipples of the wearer, and a mouth over his navel.  Countless types of helmets were constructed to accompany the gusoku armor, and the makers had a boundless imagination in their designs, drawing inspiration from animals, flowers, and even fruit (Blair 244).  Following the Meiji restoration, the feudal system that had supported the samurai was dismantled, and many pieces of gusoku armor, no longer needed, were spread across the country.  A few large collections remained, and now most reside in museums and galleries (Yamanaka, 2).

         The yoroi, do-maru, haramaki and gusoku of Japan are an integral part of its distinct history and culture. The ideals of the samurai and Bushido are clearly seen in the armor of these Japanese warriors.  Through the beauty of his armor, and his appreciation of that beauty, the warrior was able to reach a certain purity and clarity; at the same time, the defensive nature of the armor was of utmost importance in the combat that ruled his life.


Blair, Claude and Leonid Tarassuk, eds. The Complete Encyclopedia of Arms and Weapons. New York: Simon and Schuster, 1979.

Exhibition of Japanese Armour and Horse Ornaments. New York: Yamanaka & Co.: 1933.

Turnbull, Stephen. Samurai Warfare. London: Cassell & Co, 1996.

---. The Samurai Sourcebook. London: Cassell & Co, 1998.

Yamagami, Hatiro. Japan’s Ancient Armor. Japanese Government Railways: Board of Tourist Industry, 1940.

Web Resources : an online Japanese armor construction manual : an essay on the development of samurai warfare in Japan : a page offering a brief history of samurai armor and weapons : a page stemming from a role playing game, but includes excellent descriptions of samurai armor : a short description of yoroi armor

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