The Hatakeyama were descended from Taira Takamochi. As early supporters of the Ashikaga, they became very powerful as shûgo during the Muromachi Period. In the aftermath of the Ônin War, the Hatakeyama were much diminished and now represented by a number of scattered branches, the most notable of which resided in Kawachi, Noto, and Mutsu.
The Kawachi-Hatakeyama were represented at the start of the 16th Century by two main branches issuing from Hatakeyama Mochikuni (d.1455). The more powerful of the two derived from Masanaga (d.1493). Masanaga had been adopted by Mochikuni when the latter had despaired of having any natural sons. When Mochikuni did in fact a sire a son (Yoshinari), he sought to disinherit Masanaga. A civil war ensued and the two branches were often at odds thereafter.
The Mutsu-Hatakeyama held Nihonmatsu Castle in Mutsu and saw its power gradually diminish over the course of the sengoku period, until they were looked upon by their neighbors the Ashina as essentially vassals. Nonetheless, allied to the Kasai, they clashed frequently with the Date family They were largely destroyed at the hands of Date Masamune in 1586.
This branch of the Hatakeyama, based at Nanao in Echigo, was weakened by internal strife that finally brought about its ruin as an independant daimyô house in the 1570's.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005