The Incas did not have a written language but used a system of knots tied in cords called quipus. The quipus served to do accounting of business transactions and as memory aids in recounting significant events in the local history. Special training was required to interpret these quipus. While many quipus exist in museums today the meanings are lost in the passage of time. Native American peoples also used knots in cords as communication tools with methods as basic as a knotted cord for counting days to knots incorporated with wampum to be a part of story telling.
Tally systems using systems of knotted strings and cords are common in many cultures.