A summary of samurai armour over the centuries.

Each piece of armour consisted of a set of small iron plates called kozane laced together by leather cord. The resultant strips were then lacquered to protect the material against rust and then a series were tied together horizontally with silk cords called kebiki-odoshi to produce a light and fairly resilient armour plate. Beginning in the latter part of the Heian period this method produced the varying sizes and shapes of Japanese armour for several centuries. Japanese armourers tended towards manoeuvrability and preferred to sacrifice some elements of protection for this to be achieved; in the medieval period of Western Europe knights used their weight as well as that of their horses as weapons but that wasn't the case in Japan where mobility was deemed more important. 

Lacing the armour was an art in itself called odoshi and the colour and even the patterns produced by this method could enable a samurai to identify a member of a clan by the colour of the cord his armour was laced from. For example, the Taira clan adopted purple, the Fujiwara light green, and the Tachibana yellow. These cords also had their own names: light blue was called hanairo-odoshi and kon-odoshi for navy blue for example. It was quite common for armour to sport several different colours and this was known as iroiro-odoshi. White coloured lacing for a suit of armour signified that the wearer did not expect to survive his next engagement as white is the colour of mourning in Japan. The cord itself also identified the rank of the samurai. Tight, elaborate lacing was reserved for those of high rank while wide facing was used for the infantry troops.

Up to the 14th century the o-yoroi or 'great armour' was standard for the samurai. Its box-like appearance, large square sode, and equally large kusazuri was ideal for mounted warfare. Furthermore it looked beautiful and aristocratic with its multi-coloured lacing or odoshi. Finally the kabuto with its characteristic fukigaeshi (winglets or turnbacks) at the front of the shikoro (neck guard) and the kuwagata (twin horned crest) above the helmet's peak gave the samurai its enduring and appealing image.

By about the 14th century warfare in Japan was changing. Samurai were more and more fighting on foot and campaigns were becoming more protracted and lengthy; the traditional o-yoroi was getting too heavy and cumbersome for this. As a result the do-maru (literally 'torso round'), the cuirass worn by the common soldier for longer than the o-yoroi, was beginning to be adopted by the proud samurai as it was lighter and easier for the wearer to move and fight in. This cuirass looked not unlike the o-yoroi but its main difference was that it wrapped around the body and was tied under the right arm; furthermore the kusazuri was reduced in bulk and increased in number. The result was a lighter and more comfortable outfit. Another cuirass developed from this called the haramaki-do (literally 'belly-wrap torso'). This, again, was similar but opened and closed at the back.

More demands were made on Japanese armourers as warfare was fought on an even larger scale in the 15th and 16th centuries. Campaigns were becoming more protracted and samurai were spending more time in their armour. Therefore the armourers began to modify the design of existing cuirasses and the way the plates were actually laced and sewn together. The numerous cords proved counterproductive to the wearer because it absorbed a lot of water in wet weather, which put extra weight on the armour, and mud would get caught in it causing it to attract ants and lice in milder conditions. Moreover in the winter the do laced in kebiki-odoshi was in danger of freezing solid and, on the military front, the cords could retain a spear point because the stroke or lung would not glance off it easily.

What was produced by the armourers was a huge array of body armour consisting of solid strips of metal riveted together, rather than laced, and the amount of cording substantially reduced. The kusazuri were also reduced in size and were made to gently curve downwards so as to not protrude as much as they did with the o-yoroi. These suits were known as tosei-gusoku or modern armour. This included a whole swathe of suits: the nuinobe-do; mogami-do; dangaiye-do; okegawa-do; yokohagi-do; tatehagi-do; yukinoshita-do; sendai-do; hotoke-do; and uchidashi-do. Then there was the nio-do and kata-nugi do. The former included a cuirass that was shaped like a bare, male chest and the latter was a cuirass that incorporated half of that same effect and half armoured. Even parts of European armour found their way into forges of Japanese smithies. The nanban-do was a suit that often included the central, protruding ridge of the Spanish cuirass with kusazuri attachments, and the morion helmet fixed with the shikoro and sometimes the mempo if the wearer so wished it - the great Tokugawa Ieyasu was known to have worn such a suit at the battle of Sekigahara (1600).

The samurai helmet was also modified over the centuries. The shikoro began life virtually straight until the latter part of the Heian period and gradually expanded over the proceeding centuries sometimes to the extent of forming an umbrella around the helmet bowl. By the time of the Onin Wars in the 15th century the shikoro curved more downwards giving more freedom of movement to the wearer's neck and head. This also made the kabuto slightly lighter and less back heavy as the earlier types often were. Like the suits of armour there were many types of kabuto which included the naga-eboshi kabuto, o-boshi kabuto, kawari-kabuto, yaro-kabuto, tsuji-kabuto, hoshi-kabuto, ichi-no-tani kabuto, momonari-kabuto, zunari-kabuto and the chasen-kabuto. 

With the kabuto there were also many different kinds of crests (maedate). These were usually fixed in a slot above the helmet's peak and often took the form of stylised antlers but they could also be any shape or form and could just as easily occupy a socket on the side of the helmet or the back. The crest served to identify who the wearer was and might reflect his interests, his religious leanings, or his clan's mon (badge) and a myriad of other things; the formidable Toyotomi Hideyoshi wore a kabuto with a stylised sunburst at its rear.

Over the suit of armour some samurai, usually high-ranking individuals, liked to wear the jinbaori. This garment was a large surcoat and was usually sleeveless or had short sleeves. The idea of a samurai wearing a jinbaori was to give him a more impressive appearance, certainly the surcoat was often highly patterned and embroidered.

Further Reading

The Samurai (Osprey Publishing) - Anthony J Bryant

Samurai Armies (Osprey Publishing) - Stephen Turnbull.