Each modern Japanese prefecture has a unique flag, most often a bicolour geometric highly stylised design, often incorporating the characters of the Japanese writing system and resembling minimalistic company logos.
[1] The heraldic badges worn by warriors in medieval Japan (mon) were forerunners of the modern emblems used in the prefectural flags.
[2] A distinct feature of these flags is that they use a palette of colours not usually found in flags, including orange, purple, aquamarine and brown.
Some prefectures also have alternative official flags called "symbol flags" (シンボル旗).
Famous symbol flags include the one used in Tokyo.