A Sashimono or "feudal banner" were small banners historically worn by soldiers in feudal Japan, for identification during battles.
The sashimono banner hung from an L-shaped frame, the poles of which were attached to the backs of the chest armor (dou or dō) by special fittings--a socket machi-uke or uketsubo near the waistline and hinged at shoulder level with a ring gattari or sashimono-gane. Sashimono were worn by common soldiers, known as ashigaru and the elite samurai, and in special holders on the horses of some cavalry soldiers. The banners, resembling small flags and bearing clan symbols, were most prominent during the Sengoku period-—a period of long civil war in Japan from the middle 15th to early 17th century.
The designs on sashimono were usually very simple geometric shapes, sometimes accompanied by Japanese characters providing the name of the leader or clan, the clan's mon, or a clan's slogan. Often, the background colour of the flag indicated which army unit the wearer belonged to, while different divisions in these armies emblazoned their own design or logo on it. However, the presence of the Daimyo's mon was used more commonly than the design or logo of the unit, as battles could often get quite large and complicated; being able to recognize friend from foe at a glance is of the utmost importance in battle. Sometimes elite samurai, who were sufficiently famed or respected, had their own personal design or name featured on their sashimono as opposed to that of their division. These stylized designs contrast with the elaborate heraldic devices displayed by some European armies of the same period.