Emblems (kamon) of the Date clan are a typical example of accumulated heraldic symbols within one blood-related association. However, the number of kamon can be considered incredible even for the Japanese military society. Historical sources confirm that the heads of the Date clan used at least eight emblems for individual and family identification and two heraldic symbols that were applied as a decorative element of personal belongings and architectural ensembles of different years. Since the end of the 12th century, when the founder of the Date clan received the first kamon from Minamoto no Yoritomo as a reward for faithful service in the war against the Ōshū Fujiwara clan, and until the end of the Edo period when the feudal system ceased to exist, the design and status of the emblems have been changed many times. This paper studies the visual transformation of the Date clan emblems between the end of the 16th - mid 19th centuries, as the majority of preserved historical sources are dated as part of this period. The analysis of artifacts and documents showed that the highest increase in the number of kamon of the Date family occurred between the last third of the 16th century - first third of the 17th century. The new emblems included those that heads of the clan received as a reward for faithful service and those that they created as a declaration of aesthetic principles. Furthermore, the range of tangible objects, which were marked with emblems, significantly expanded. Kamon became an integral part of everyday life and in many cases, the emblems were not only a mark of property but also a decorative element. Probably, for this reason, the composition of kamon is both stabilized and complicated.