A simple, relatively light form of armor, chain mail was one of the main forms of defense during the Middle Ages. As opposed to the heavier, more protective plate armor, chain mail consists of various interlocking links throughout. Chain mail was never designed to completely protect the wearer, as the energy of a blow would be transferred into the body with minimal resistance, leading to fractured and broken bones. The purpose of chain mail was to deflect glancing blows and to protect the body from cuts and gashes, which it excelled at. A strike from a sword would be able to break a bone, but the medicine of the time was sufficient enough to set and heal a broken bone (although not perfectly). An open wound, however, was likely to become infected, which the doctors of the time were not able to reliably treat. Chain mail became obsolete after the construction of firearms, which made the armor entirely useless. During World War One, experiments were carried out to determine whether or not chain mail would be an effective bulletproof material. Testing proved that chain mail actually increased the damage a bullet caused to a body, by fragmenting and carrying more metal into the wound. Chain mail did, however, find limited use in masks designed to prevent shrapnel damage, which proved effective in testing but in practice were unpopular with soldiers due to the appearance and weight.
In more recent times, modernised chain mail can be seen in protective gloves for butchers and others who use sharp cutting tools, as well as in shark-proof diving suits.
There are many different ways of making chain mail, and these different methods are known as weaves. The most common (and well known) weave is "European 4-in-1", which is the type seen in the image displayed above. This is the main type used for armor throughout Europe, but was also seen in Asia. The 4-in-1 part of the name refers to the layout of the rings; every one ring is connected to four others. There are variants such as 6-in-1 and 8-in-1 which makes for a tighter (but far heavier) weave that offers more protection at the cost of weight and flexibility (as well as cost).
The other most common type of weave used for armor is the Japanese weave. This type usually comes in 4-in-1 or 6-in-1 patterns, and is laid out very differently to the European style. The "main" rings are laid out horizontally in a cross or hexagonal pattern, and smaller vertical rings are used to connect them. This style can appear more ornamental than the European weave, and was used more often to connect plates of solid armor rather than to provide protection by itself. As the name suggests, this style of chain mail was found mostly in Japan.