The Japanese word for “heraldry” is monshō-gaku, 紋章学, which literally translates into “science of insignias”, where gaku means “study / science” and monshō “insignia”. However, Japanese people usually use the word kamon rather than monshō to designate heraldic emblems. The word kamon is composed of two characters: 家紋, where 家 means “house” or “family” and 紋, “mark”. Furthermore, the character 紋 divides itself into 糸, “thread”, and 文, “script” or “decoration”, which shows that 紋 probably designated at first embroidered designs on garments or fabric. In fact, kamon is not the only term that designates a heraldic emblem. One may also use monshō, as indicated earlier, but also mondokoro, daimon, jōmon, etc., or simply mon.
Here are the most common words used in Japan:
KAMON OR CREST
When talking about Japanese heraldry in a foreign language, one needs to find an appropriate translation for the word kamon. In English, people generally use the “crest” or “seal”. This is convenient, but unfortunately far from accurate. A seal is a device generally made of stone, wood or metal, on which a specific design is carved, and used in order to make an impression so one can authenticate a document. If seals do exist in Japan, they are in most cases carved with Chinese or Japanese characters, and almost never feature any heraldic sign. Consequently, we prefer to refrain from using “seal” when translating mon into English. We face the same problem with “crest”. In Western heraldry, the crest is a very specific element of a coat of arms, situated at the top of the helmet and considered a heraldic embellishment. Thus, the modern use of “crest” as to refer to an entire heraldic achievement is erroneous, and similarly, one cannot speak of a “crest” to denote a kamon. Indeed, some Japanese warlords had sometimes used a mon in place of a crest on their kabuto, but this was not the norm. In fact, most of the crests on Japanese armours were not from heraldic inspiration at all.
Western heraldry uses a specific vocabulary and has a very complex system of rules that governs how the colours (tinctures) are associated, where the elements (ordinaries, charges, embellishments, etc.) should go, who can use orders’ insignias or other elements, etc. A “crest” refers only to the device attached at the top of the helmet and cannot be used to refer to anything else. Japanese heraldry on the other hand, if not devoid of rules, is based on a far less complex system. It boils done basically to a single design featuring (or not) an enclosure; both components do not follow specific rules. The closest thing to a mon we can find in Western heraldry is what we call a “badge”, a para-heraldic insignia associated to a person or a family, often worn on garments. The use of badges was more flexible than that of full heraldic achievement, and badges were thus adopted during casual events.
We therefore think that the best words to translate mon into English are insignia, badge or emblem, rather than seal or crest.