The clan made its chief seat of governance in the area around the Hiratsuka Shrine in what is today the Nakazato area of Tokyo's North Ward (Kita-ku), and expanded their influence over the years to cover a much wider area, delegating much of it to branch families such as the Miyagi, Takinogawa, Shimura, and Itabashi clans.

He expanded and solidified the clan's control over the districts of Toshima, Adachi, Tama, Niiza and Kodama.

Terutoki's birth father, Hōjō Tokiyuki, was hidden and protected at Shakujii during the Nakasendai Rebellion (1335) by Toshima Kagemura; since Kagemura lacked a male heir, Terutoki was adopted to succeed him as clan head.

Another temple strongly associated with the clan, Sanbō-ji, was established to the east of Shakujii castle in 1394.

It is said to have been moved to its current location on the edge of Sanbō-ji Pond, one of two ponds which form the center of modern-day Shakujii Park, by Ōta Dōkan, following the destruction of the Toshima clan by his hand in the late 1470s.