In the Muromachi period and the following Warrior Society (15c-16c), the shape of the family emblem became more abstract and refined than before. At the same time, these family emblems came to be used by the warrior class as heraldic markings. They played a significant role in the warrior society of that time. You may have seen scenes in some movies of battle flags with family emblems waving over the battle field, or of a group of soldiers sitting on benches surrounded by encampment curtains with a family emblem.
By the Edo period (17c-19c), at the height of the feudal era, the use of these emblems was established throughout Japan. What heraldry eventually became in Japan was a system of family emblems–the use of a distinctive mark as a symbol of one’s family name. During the Edo period, the haori, a half-length coat, was popularized as a formal garment. The standardization of these garments led to the final formalization of the design of family emblems since they were now displayed on official garments used in formal settings.
The family emblem played a significant role as a symbol of lineage. The design of most family emblems was emphasized by enclosing them in a circle. Among the lower classes, it became popular to wear emblems showing a family mark similar to those used by upper-class families. Lower-class families devised many kinds of emblems resembling those used by the upper classes. They even developed a new style of their own. These emblems seem to have served as a sort of business card.