Masakado was a member of the Kammu Taira clan of Japan. He was the son of
Taira no Yoshimasa, Chinjufu-shōgun. His childhood name was Sōma no Kojirō (相馬小次郎). Taira no Masakado was a powerful landowner in the Kantō region. He is regarded as the first bushi because he was the first to lead a self-governing party.
His life is detailed in the Shōmonki (将門記), a long and highly detailed monograph about his life believed to have been completed as early as the 940s by an anonymous author. Due to the religious and political nature of the account, it was most probably written by a monk or aristocrat closely connected to Masakado himself.
, the sorceress, is shown carrying a sword in one hand, a bell in the other, and a torch in her mouth; the toad, her familiar, is shown in the inset with her father, Taira no Masakado. Ukiyo-e
woodblock print by Yōshū Chikanobu
In 939 (Tengyō 2, 12th month) during the Heian period of Japanese history, Masakado led a minor rebellion which is also known as Tengyō no Ran. The armed struggle began when Masakado led an attack on an outpost of the central government in Hitachi Province, capturing the governor. In December of that year, he conquered Shimotsuke and Kōzuke Provinces; and he claimed the title of Shinnō (New Emperor).
Masakado killed his uncle Kunika who was part Taira. The central government in Kyoto responded by putting a bounty on his head, and fifty-nine days later his cousin Taira no Sadamori, whose father Masakado had attacked and killed, and Fujiwara no Hidesato, killed him at the Battle of Kojima (Shimōsa Province) in 940 and took his head to the capital.
The head found its way to Shibasaki, a small fishing village on the edge of the ocean and the future site of Edo, which later became Tokyo. It was buried. The kubizuka, or grave, which is located in the present day Ōtemachi section of Tokyo, was on a hill rising out of Tokyo Bay at the time. Through land reclamation over the centuries, the bay has receded some three kilometers to the south.
After Masakado's death, his daughter Takiyasha continued living in the ruins of his former shōen, in the lands of the Sōma.