Minamoto clan (源) was one of the surnames bestowed by the Emperors of Japan upon members of the imperial family who were demoted into the ranks of the nobility. The practice was most prevalent during the Heian Period (AD 794-1185), although its last occurrence was during the Sengoku Era. The Taira were another such offshoot of the imperial dynasty. The Minamoto clan is also called the Genji (源氏), using the Sino-Japanese pronunciation of the Chinese characters for Minamoto (gen) and family (ji). The Minamoto were one of four great clans that dominated Japanese politics during the Heian period -- the other three were the Fujiwara, the Taira, and the Tachibana. See "Minamoto Clan". Wikipedia. Retrieved 2014-12-14. Kamon (家紋), also Mon (紋), monsho (紋章), and mondokoro (紋章), are Japanese emblems used to decorate and identify an individual or family.