Tosei Gusoku The Final Form of Japanese Armor

Table of Content

• What is Tosei Gusoku 当世具足
• History of Tosei Gusoku
• Features of Tosei Gusoku
• Major Parts of Tosei Gusoku

What is Tosei Gusoku 当世具足

Tosei Gusoku, the Japanese name 当世具足 means “modern armor” in English, is a type of Japanese armor developed during the Sengoku period. Tosei Gusoku is the culmination of Japanese armor development, inheriting the characteristics of other armor types like Oyoroi, Domaru, Haramaki, etc. It was designed as practical armor but often featured elaborate decorations to make it look distinctive and unique.

What is Tosei Gusoku made of?

The main material of Tosei Gusoku are Iron, steel, leather, lacuqer, silk and other fabrics. Iron, steel and harden leather were made in to large scales (Itazane) and compose the major parts like chest plate and helmet. Lacquer (Urushi) was applied to both iron and leather to protect them and add a decorative finish. Silk was used for lacing and undergarments, with other fabrics used for padding and covering parts of the armor for added comfort and mobility.

Weight of Tosei Gusoku

Mobility was emphasized in the production of Tosei Gusoku, while maintaining sufficient protection, the weight was not too heavy. The typical weight of Tosei Gusoku was around 20 kg (44 lbs). The armor was usually custom made, designed to fit the body well, so wearer might not feel too heavy.

History of Tosei Gusoku

Japanese warfare changed a lot over time, so did the weapon and armor used by samurai. During the Heian period, battles were mostly one-on-one mounted archery. High-ranking samurai would announce themselves and shoot arrows at each other on horseback. They wore o-yoroi armor and used Yumi (bows).

Later, battles became group fights on foot. Even high-ranking samurai had to fight in close combat. The main weapons were Naginata (pole weapon) and Yari (spear). Armor became lighter and more mobile, like Domaru, Haramaki, and Haraate.

During the Sengoku period, battles got even larger, and firearms were introduced. This created a need for armors that should have better protection, easy movement, and mass production. Tosei Gusoku armor was developed in response.

Tōsei Gusoku first appeared in the late Muromachi period and was fully developed during the Azuchi-Momoyama period. Its main feature was full-body coverage without gaps. A complete set included kote (armored sleeves), haidate (thigh guards), and suneate (shin guards), offering more protection than earlier armor types.

In the peaceful mid-Edo period, the Edo shogunate shifted from military rule to civil governance. Samurai, used to lived by their katana, were no longer needed on the battlefield. And Tosei Gusoku change from practical combat gear to ceremonial item, decorated for rituals.

With added non-functional decorations, Tosei Gusoku was no longer practical armor. Interest in medieval armor led to revival-style Tosei Gusoku, but these often had excessive decoration, becoming more of an artisanal product.

During the Boshin War in 1868, the introduction of modern combat techniques and firearms by Western-style armies revealed the ineffectiveness of Tosei Gusoku as armor, marking the end of its era.

The Name “Tosei Gusoku” means modern armor, as to distinguish it from the armor before the 16th century (About Sengoku period), known as "old-style armor 昔具足."

Features of Tosei Gusoku

Great Mobility

Tosei Gusoku offers excellent mobility for both mounted and foot combat. Unlike oyoroi, which was designed for mounted archery, or Domaru, which was for foot combat, Tosei Gusoku is more versatile. The gaps in Tosei Gusoku were designed to allow the wearer to move smoothly. For example, the shoulder guards (sode) and thigh guards (haidate) were crafted to protect against enemy attacks while allowing a wide range of movement in the shoulder and hip joints. The long lacing (yurugi no ito) was shortened to reduce weight and allow more freedom of movement in the waist. The shoulder guards (sode) were also smaller compared to oyoroi.

Better protection

With the introduction of firearms, Tosei Gusoku needed to provide better protection. More and thicker iron plates were used, with some armor chest plates even adopting Western designs like the Nanban-do. Japanese would test the armor with Tanegashima guns, and bullet marks on the armor were a sign of good protection.

Cheap to produce

Tosei Gusoku evolved from Domaru but was optimized in many ways. For example, instead of small scales, Tosei Gusoku used large scales or replaced them with plate structures (ita-zane) or even solid plates, making it easier to produce in large quantities. The use of iron for these plates improved their defensive capabilities. Due to the loss of flexibility, a hinge mechanism was introduced for easier wearing and removal of the cuirass.

Eye catching decoration

Another special feature of Tosei Gusoku is the extensive decoration added to the armor. These decorations served as identification on the battlefield and allowed samurai to express themselves, unlike traditional armors where the color of the lacing was the main distinguishing feature. In Tosei Gusoku, unique or even exaggerated designs could be seen on parts like the maedate (front crest), wakidate (side crests), and menpo (face guard).

Major Parts of Tosei Gusoku

Fukikaeshi (吹返) : On Tosei Gusoku helmets (Kabuto), the fukikaeshi (side flaps) became smaller and turned into simple decorations. Some helmets were made without them from the start.

Shikoro (錣) :The shikoro (neck guard) on Tosei Gusoku helmets was designed to be narrower to better protect the neck, reflecting the more intense combat. A common style is the "Hineno shape" (日根野形).

Wakidate (脇立) : The wakidate (side crests) on the helmet often used deer or buffalo horns. To avoid interference in battle, they were made from light, breakable materials like paper or wood.

Maedate (前立) :The maedate (front crest) on the helmet often displayed the samurai's personal beliefs or family kamon.

Menpo (面頬): The menpo (face guard) appeared in the late Heian period and evolved through the Muromachi to Azuchi-Momoyama periods. It protected the face and often had designs to intimidate the enemy, like the faces of old women or demons.

Sage (下げ) : The sage (throat guard) is part of the nodowa (throat armor), made of small, tiered plates shaped like fan paper.

Sode (袖) : The sode (shoulder guards) in Tosei Gusoku, sometimes called "Tosei sode," became smaller over time to allow more arm movement, compared to the larger ones (Osode) used in the past to block arrows.

Do (胴) : The do (cuirass) needed to be stronger to defend weapons like guns and spears. Large iron plates replaced smaller scales, and a hinge system made it easier to wear and remove. This simplified production and allowed for mass production for large-scale battles.

Tateage (立挙) : A notable feature of Tosei Gusoku do is that the tateage (upper section) and the nagakawa (lower section) each have one more tier than older armor styles, with three tiers in the front and four in the back.

Nagakawa (長側):  The nagakawa (lower section) of Tosei Gusoku usually has five tiers, reflecting an increased focus on full-body protection.

Hikihaseno-o (引合緒) : The hikihaseno-o (cords) are used to tighten the do and are attached at the right side.

Dosakino-o (胴先緒): The dosakino-o (bottom cords) are used to tie the bottom of the do.

Kote (籠手) : In Tosei Gusoku, kote (armored sleeves) are often attached to the do for full-body coverage.

Yurugi no ito (揺糸) : To enhance mobility in large battles, the yurugi no ito (connecting cords) between the do and kusazuri (tassets) were lengthened, allowing for greater movement.

Kusazuri (草摺) :Tosei Gusoku did not have a fixed style for the kusazuri (tassets), so the number of sections and spaces varied.

Haidate (佩楯): Haidate (thigh guards) protect the area between the kusazuri and suneate (shin guards) and have evolved since the Nanbokucho period as battles became more intense.

Suneate (臑当) :Suneate (shin guards) protect from the knees to the ankles and have been used since ancient times. In Tosei Gusoku, they were typically made as part of a matching set with the armor and helmet.