Tanko (armor) (短甲)
Tanko is one of the formal names of Ko (armor) used between Yayoi Period and Tumulus Period.
The Tanko were made of wood, leather and iron, basically protecting the torso from shoulder to waist. They were body armors.
They were unearthed mainly as burial goods, and the tanko can be seen in design of haniwa and stone sculptures. They were crafted to fit human torsos using square and triangular iron plates or leathers, those plates or leathers were tacked down and equipped with opening and closing hinge apparatus. They have slender waists.
The Ko (armor) unearthed as burial goods have 2 forms, and the name 'Tanko' was applied corresponding to armors for foot soldiers and cavalrymen in archaeology or historical science of Meiji era because 'Tanko' and 'Keiko (lacquered armor for ceremony)' appeared in the document of Nara period "Todai-ji Temple Kenmotsu-cho (Lists of Treasures dedicated to Temples)"(in 756) and "the Engishiki" (an ancient book for codes and procedures on national rites and prayers). According to documents, 'Tanko ichiryo' means the armor covered only torso and 'Tanko ichigu' means complete equipment including Kusazuri tassets, samurai warrior helmet, pauldron, neck armor, gauntlet and shin guard, though there is no example of complete equipment unearthed.
The Tanko existing now are mainly made of iron or gilt bronze, however, some pointed out that it is possible organic material was also used to make them and various Tanko made of organic material such as wood, leather and knitted plant fiber with lacquer on it were unearthed from the remains of the late Yayoi period in recent years. The wooden Tanko was crafted by hollowing out the log other than curved part or by putting square plants together with lacquer on it, and some of them have decoration such as pattern and color on it.
The wooden Tanko used the form binding the back part and chest part (torso) made separately together by thread, unearthed from the ditch of Iba remains in Hamamatsu City, Shizuoka Prefecture of the late Yayoi period, and from the ditch of Tsuboi remains in Kashihara City, Nara Prefecture of Tumulus period. The former Tanko was made of a willow, and the frontal torso part and back part have been unearthed. There are patterns such as doshinen-mon design, spiral-mon design, parallel lines-mon design, feather-mon design and triangle-mon design clearly curved convexly on them. And those patterns are two-toned with red pigment and black lacquer. They are believed to have been used as a ceremonial implement not used in an actual battle since they are made of wood and have magical patterns.
The Tanko made by iron appeared in Tumulus period, and Yokohagiitabyodome (nailing horizontally long iron plates together) prevailed as a stable form. By 6th century, Keiko had replaced them and Tanko made after that were not unearthed.
The armors used by Chinese foot soldiers had so much effect on them that Keiko made around the same time influenced by armors for cavalry of nomad in northern China was found. And some suggested the opening and closing system of torso part used on Tanko was inherited by Oyoroi (big armor) in Heian period.
Tanko made of iron triangular plates bound with leather: Nagatoronishi remains (Takasaki City, Gunma Prefecture)
Tanko made of horizontally long iron plates bound with leather: Kitsuneyama kofun-tumulus (Kaga City, Ishikawa Prefecture)
Tanko made of 17 iron plates bound with leather: Omaruyama kofun-tumulus (Kofu City, Yamanashi Prefecture)