Kamon 家紋 (Family Crests)
Kamon[家紋/かもん] are the japanese family crests. There appeared during Heian period (794-1192).
But some scholars say that even during “Asuka-Period” you can already see attempts at “kamon” being introduced.
The origin of “kamon” is that aristocrats placed their favorite designs of plants and flowers on clothes and cow carriages. After that, warriors began to use “kamon” with more geometric designs on their flags to identify themselves on the battlefield. Most the warrior class and even samurai wore their crests.
In Edo period (1603-1867), powerful merchants and “kabuki” actors were permitted to use “kamon”. During Edo it became a trend to show off the family kamon via the kimono/yukata a person was wearing.
And ordinary people have been able to use “kamon” since the Meiji period (1868-1912).
Nowadays, there are over 10,000 “kamon” in Japan. There is a chrysanthemum which is the family of the emperor can only use. Every bigger japanese family has a personal “Mon”, but their significant meaning has decreased. They are sometimes used in a company emblem and derive from more traditional mon. (Example: Mitsubishi)