The term "Kamon" refers to a crest used in Japan to indicate one's origins; that is, one's family lineage, blood line, ancestry and status from ancient times. It is also referred to simply as “Mondokoro” or “Mon”. It is said that there are more than 20,000 distinct individual Kamon in Japan. Kamon is a unique culture and tradition you can find only in Japan.
It can be said that Kamon is an example of Japan's own culture which has been in use up to the present day. A Kamon was created to serve as an unique emblem that represented a family's identity, clearly revealing the family name of its owner. Later, Buke (samurai warriors) and Kuge (the nobility) made use of Kamon, which are classified into some groups according to blood line or historical origin. Each group consists of representative Kamon and their variations. Kamon spread widely and were used on even graves, furniture, and ships. It was natural for Kamon to be placed on weapons like Samurai Sword (Katana) and Samurai armor (Kacchu). However, although there were no limitations placed upon usage, freely using other family's Kamon caused friction or conflict. Especially using Kamon of a higher class, such as Daimyo (Japanese feudal lord) or Shogun (general) created more friction. Hence, there was an unspoken rule to avoid using the Kamon that is already used by high class clan or family as much as possible.
During the peaceful, tranquil, rather uneventful, Edo Period, there were few hard battles fought among samurai so, the former practical role of Kamon, such as; distinguishing friend from foe in battle, had changed to be a kind of symbol of authority. Japan was a hierarchical society of samurai, farmers, artisans, and merchants during the Edo period, and Kamon were used as a means of indicating the social status of your family to others and ascertaining the social standing and lineage of others, enabling you and your family to dress accordingly. In addition, Kamon were possessed and used by common people as well. This was in stark contrast to European countries, where only aristocrats could use a crest. Farmers, tradesmen, craftsmen, and even entertainers like Rakugo story tellers, actors, and Yujo (prostitute) used Kamon. At the end of the Edo Period, Kamon designs were reputed highly and used for pictures of Japonism in art nouveau in Europe. In addition, from an aesthetic aspect, Japanese Kamon are well known abroad because of the symbolic design and simple structure, and is often used in various designs.