Oyoroi (O-yoroi) is a yoroi armor used from Heian era to Kamakura era (AD 794 ~AD 1336),
and it was made for fights with archeries on horse.
As “Oyoroi” is larger than other yoroi armors after Middle Ages, it is called so formally.
As for materials, industrial art technology and aesthetic sense are synthetically
gathered into one with iron, cow leather, deer leather, silk, ropes or colorings.
The Epoch of Oyoroi
Oyoroi started to be made from Heian era (AD 794 ~AD 1192). At this era, country
samurais gained power and samurais with horses were vigorous.
Considering armors or weapons used in battles, it is known that they mainly fought on
horses using archeries.
The battle on horse with archery was formal. First, both samurais on horses declare
their name, run to approach another, and shoot each other.
When meeting the enemy, they should meet them on the left side so that it would be
easier to shoot with the right hand.
The Structure of Oyoroi
The basic structure of oyoroi is dou, waidate, sode and kusazuri. Kote and suneate pertain.
Dou is made by connecting kozane (little boards of 5-7cm made of iron or leather).
In the front of dou, tsurubashirikawa, made of deer leather is pasted, and this is
for protecting the chest and to make the surface smooth so that the string will not
be caught by the kozane of the dou.
In order to male kozane as light as possible, main parts were made by iron and
other parts were made by leather.
To create one oyoroi, about 2000 kozane were used.
The right side of dou has a gap because strings attach parts, so samurais used to
equip strong iron waidate to protect there.
To protect thigh, kusazuri was equipped under dou.
Osode was equipped on the outside of shoulders and upper arms, and it was used
as mobile shield.
Furthermore, on the upper-right side of the chest, sendannoita is attached and
on the upper-left side of the chest, kyuubinoita is attatched.
Those are little rectangular protectors, and they protected samurai from arrows.
The advantage of oyoroi is that it “protects by mainly attacking”.
Western chivalries’ armors protect the whole body from the head to the feet
and these are good for protection, but their disadvantage is that they lack of activity and speed.
On the other hand, oyoroi is stretchable on the whole, so you can turn or bend
the body on fighting on horse.
So you can move the both arms freely when shooting or using huge swards.
Oyoroi is a complete armor which is adequate to both protection and attack.