Scale Mail

This is a coat of soft leather covered with overlapping pieces of metal, much like the scales of a fish. It is just as heavy as chain mail, but offers slightly worse protection. It has no significant advantages over hide or brigandine.
Scale mail is an old type of armor, much like splint mail. It never became popular in western medieval culture for very long; its production was found to be too time-consuming and thus less efficient to make in comparison to other armor types. In the game context, scale mail is most common in Dark Age periods, in foreign cultures, or in those areas where its materials are unusually plentiful.
Some human cultures, notably those similar to the Byzantines and other eastern and southern kingdoms, did not pursue the evolution of armor made of large plates, but rather chose to make use of small plates. Where metal is not forged but is instead cut from sheets of malleable metal ores, the technology of scale mail and its successors (splint, brigandine, and banded armor) predominates.
This is not a matter of primitive versus civilized, but rather two separate approaches to the same problem. Where western cultures stress protection, eastern cultures seek to maximize flexibility (and ventilation in the hotter climates).
The scales in scale armor are made smaller in order to make the suit more flexible and comfortable when worn. Indeed, in this respect, scale mail far exceeds either plate or banded mail.
However, all those scales require more maintenance, as the more items attached to an armor's backing, the greater the chance some will fall off. Scale armor not properly maintained loses one level of armor class protection.
Scale mail suffers the same problems of dirt, grime, lice, and odor that studded leather and padded armor suffer.
Scale mail does offer protection as good as that of brigandine for the same price and at a comparable weight. The choice between scale mail and brigandine armor is likely to be determined by the nature of the cultures in the campaign world.