* Image is for illustrative purposes only.Taira no Sadamori
平貞盛
The Heian Warrior Who Slew His Cousin Taira no Masakado — Ancestor of the Ise Taira Line That Produced Taira no Kiyomori
Description
Life
Taira no Sadamori was a member of the Kanmu Taira clan, born as the son of Taira no Kunika, Deputy Governor (Daijō) of Hitachi Province. Around 935, while serving in the capital as a Left Palace Stable officer, a conflict broke out between his cousin Taira no Masakado and Sadamori's uncles, and his father Kunika was drawn into the fighting and killed.
The Suppression of Masakado's Rebellion
Rather than seeking immediate revenge after his father's death, Sadamori resigned his post and traveled east. He initially attempted to subdue Masakado together with his uncles but was thwarted by Masakado's strength, returning to the capital again in 938. He subsequently gained the cooperation of Fujiwara no Hidesato, Deputy Governor of Shimotsuke, and in 940 advanced on Masakado's base in Shimōsa Province, defeating and killing him in the battle known as the Battle of Kitayama. For this achievement he was granted the junior fifth rank, upper grade, and went on to hold posts including Chinjufu Shōgun (Commander of the Pacification Headquarters), Governor of Tanba, and Governor of Mutsu, becoming known as the "Taira General."
Lineage and Descendants
Among Sadamori's descendants, the line of his fourth son, Koremasa, settled in Ise Province and became the founding line of the Ise Taira, from which Taira no Kiyomori later emerged. The same line is also said to have produced Hōjō Sōun, founder of the Later Hōjō clan in the Sengoku period, making Sadamori the point of origin for a warrior lineage that runs from the late Heian period all the way into the Sengoku era.
Later Reputation
Taira no Sadamori is remembered both as the man credited with suppressing the rebellion of Taira no Masakado and as the founding ancestor of the lineage that would produce the Ise Taira and, eventually, the regime of Taira no Kiyomori — making him a key figure in the history of the formation of Japan's warrior class during the Heian period.