Gien (1155 - April 25, 1181) was a priest at the end of the Heian period and the eighth son of MINAMOTO no Yoshitomo.
His mother was Tokiwa gozen. His childhood name was Otowakamaru. He had Zenjo ANO as his older brother and MINAMOTO no Yoshitsune as his younger brother. He was the younger paternal half-brother of MINAMOTO no Yoritomo. He had Yoshinari AICHI as his son.
Initially, he became a priest at Enjo-ji Temple and was called Kyonokimi Ensei, and served as a bokan (a priest who served the Monzeki families) for Cloistered Imperial Prince Ene, Prince of Emperor Goshirakawa. He is believed to have been called 'Kyonokimi' in relation with his father-in-law, Naganari ICHIJO, to whom his mother remarried, and it seems that he served Ene through his father-in-law's connections.
When his older paternal half-brother, MINAMOTO no Yoritomo, rose up in arms to overthrow the Taira family, he joined under that command and changed his name to Gien. Further, there is a view that Gien didn't go to Yoritomo's location but directly entered Owari and rose up in arms on his own. In 1181, when his uncle, MINAMOTO no Yukiie, rose up in arms at Owari, he joined their camp as reinforcement under the orders of Yoritomo. At the edge of the Nagara-gawa River, they faced the army of TAIRA no Shigehira and others (the Battle of Sunomatagawa). At this opportunity Gien attempted to attempt the enemy's camp alone at night, but he failed. After fighting TAIRA no Moritsuna (also known as Takahashi saemon no jo), a member of the Taira family, he was killed. Died at the age of 27.
His remaining son, Yoshinari, came to possess Echinosho (the present-day Aichi-gun, Aichi Prefecture) and thus became an ancestor of the Aichi clan. Also, the tomb of Gien is located in a field of Kamijuku, Sunomata-cho, Ogaki City, Gifu Prefecture, and has been selected as an important cultural property of the former Sunomata-cho Town.
Nearby is 'Gien Koen' (Gien Park), which contains the 'monument of the Battle of Sunomatagawa,' 'Gien Jizo,' and the 'memorial tower of MINAMOTO no Gien.'