Originally, “mon” or family crests were used in Japan in much the same way that nobles in Europe used heraldic devices. Imperial court families have been recorded using “mon” in the 8th century, but the practice was not very widespread or rigorous. With the rise of the samurai class, there was a greater need for identification of friend and foe and “mon” proved popular and easy forms of identification. The wars of the centuries prior to the peace of the Edo period spread the popularity of crests throughout the samurai class and also saw the nobility adopt the custom.
Family crests became highly developed and popular during the Warring States and Edo periods, but can be found mentioned as far back as the Nara period (710-794) in the imperial court. Early crests were often simple: the 12th century wars between the Minamoto and the Taira families took place under simple red and white banners (friendly competitions in schools or on television are still conducted under these colors).