The history of家紋 (Kamon) The history of Japanese family crests (Kamon) is long and ancient, with records dating back to the Heian period (794-1185). During the Kamakura period (1185-1333), warriors started putting their family crests on the battlefield flags for identification purposes. Over time, the use and design of family crests became more refined, with compositions featuring plants, flowers, objects and lines. They were generally categorized into floral, plant, martial, animal, natural and geometric patterns.

Entering the Edo period of Tokugawa Shogunate, kamon became symbols of a warrior's lineage and prestige. On official occasions, it became customary to wear formal attire embroidered with family crest. In this period of time, apart from the warrior class, the commoners including farmers, merchants and workers were not entitled to family names, so the graphical family crests carried symbolic meanings for their families as well, as a self identity.

The Shinsengumi members were no exception. Each of them had their own family crest:
近藤勇 -丸三引字
Hijikata Toshizō - Hidari-mitsudomoe (左三巴)
Yamanami Keisuke - Mitsuba-tachi-aoi (三葉立葵)
Serizawa Kamo - Aogai-uchiwa (揚羽蝶)
Okita Sōji - Maru-karagokoro (丸唐木瓜)
Nagakura Shinpachi - Matsukawahishi (松皮菱)
Saitō Hajime - Maru-kuhara-sasa (丸九枚笹)
Inoue Genzaburō - Maru-iziji (丸井字)
Tōdō Heisuke - Todō-tsuta (藤堂蔦)
Shimada Kai - Maru-sankaku (丸三角)

Each family has its own kamon, but would there be any chance that clashes? In the past, there was no registration required for kamon. Any emblem or design could be adopted, except the Emperor's chrysanthemum crest and the sun and moon crest, as well as Tokugawa kamon. These were strictly prohibited for civilian use when Tokugawa Ieyasu became shogun. It is worth mentioning that the current Japanese passport also features the sixteen-petal chrysanthemum as the national emblem. By estimation, there are over twenty thousand different family crests. In the past, without a unified recording system, clashes between crests were unavoidable and quite common. Especially from the Edo period onwards, commoners began to create family crests for their own families, often based on their recognition of the crests used by noble and warrior ancestors.

Yamanami Keisuke, commander of the Shinsengumi, once came across the roof tiles of Koryu-ji Temple close to the Yagi residence, engraving with the Mitsuba-tachi-aoi kamon, very similar to his own. He took the initiative to talk to the temple's head priest, and they became close friends afterwards. Similarly, Serizawa Kamo's kamon, the Aogai-uchiwa, is the same as the crest of the Taira clan from the 12th century, as recorded in their famous tale, The Tale of the Heike, which chronicles the power struggles during the periods of Taira no Kiyomori and Taira no Munemori (1156-1185). Hijikata Toshizo's kamon, the Hidari-mitsudomoe, is also identical to the crest of Yamamoto Kansuke, a military strategist of the Takeda clan during the Warring States period of the 16th century.

As time progresses, the use of kamon in Japanese society is gradually diminishing. However, the concept of a family crest representing a household or group still remains deeply ingrained in the minds of the Japanese population. Therefore, it's common for companies to adopt their own corporate emblems to enhance employees' sense of belonging and team cohesion.