Sakai-Senke is the head family of the House of Sen.
Though the Rikyu family had scattered in all directions after SEN no Rikyu killed himself by the sword, they were pardoned by Hideyoshi TOYOTOMI with the entreaty by Ieyasu TOKUGAWA, Toshiie MAEDA, and others, and thereby Doan SEN, the fugitive legitimate son of Rikyu, returned to Sakai City, Osaka Prefecture, and inherited the family estate (It is said that he was in hiding at the place of Arishige KANAMORI in Takayama City of Hida Province, or Awa Province.)
Sakai-Senke had the blood relationship with Rikyu, however, ended because Doan had no legitimate son (although his daughter married to the son of Soan MOZUYA, the adopted son-in-law of Rikyu).
Arishige KANAMORI (Unshu), the natural father of Shigechika KANAMORI. He served Hideyoshi and Ieyasu.
The derived school:
The Sekishu school
Founded by Sowa KANAMORI (the second name of Shigechika KANAMORI), the first son of Arishige KANAMORI.