The Hōjō clan based themselves in a northern part of the Izu Province, which was in the east (Kanto region) and quite far away from the imperial center of power in Kyoto.

Tokimasa was born in 1138 into the influential local magnate Hōjō clan in the province of Izu.

Tokimasa later married to Maki no Kata, who became his second official wife, and they had another son, Hōjō Masanori, in 1189.

[2]: 147 When he returned, the first appointments of shugo and jitō, the stewards and constables of the Kamakura bakufu, were apparently granted.

The Revenge of the Soga Brothers incident occurred on June 28, 1193, during the Fuji no Makigari hunting event arranged by shogun Minamoto no Yoritomo and prepared by Tokimasa.

In Azuma Kagami and Soga Monogatari, after killing Suketsune, Tokimune also attempted to assassinate the shogun Minamoto no Yoritomo, which is interpreted as a result of Tokimasa's secret maneuvers.

Tokimasa had entered Suruga Province and Fujino in advance, before Yoritomo, as a preparation for his secret plan.

[5] Hiroyuki Miura,[6][7][8] along with many others have debated that it was through Tokimasa's strong relation to the Soga brothers that led Tokimune to attack the shogun.

The most powerful person there (not counting the remaining Minamoto members and the Hōjō) was Kajiwara Kagetoki, the governor of Sagami.

Though he was very close with Yoritomo and trusted by Tokimasa, Yoriie disliked him, and he was executed in Suruga by the shogunate army in 1200.

[citation needed] Yoshikazu began suspecting foul play based on the actions and behaviours of Tokimasa, Masako, Ichiman and Sanetomo.

[citation needed] With the help of Ōe no Hiromoto, a trusted ally, Tokimasa found out about the plan and invited Yoshikazu to his home in Kamakura for Buddhist services.

[citation needed] After Yoshikazu exited the temple, troops belonging to the shogunate and Hojo clan, executed him.

[citation needed] After the death of Yoriie and Ichiman, Tokimasa installed Yoritomo's second son, Minamoto no Sanetomo, as the next shōgun.

Yoshitoki and Tokifusa, who enjoyed good relations with their brother-in-law, protested, but Tokimasa ordered the execution of Hatakeyama himself.

In 1205, Yoshitoki heard rumors from samurai and retainer that Tokimasa was planning to have Shogun Sanetomo assassinated.

Yoshitoki, furious, and Masako, who was also scared about the fate of her last son, put Sanetomo under protective guard and had Hiraga executed in Kamakura in 1205.

Tokimasa retired to a Buddhist monastery in Kamakura where he lived out the remaining years of his life, dying in 1215 at the age of 78.