|Born||14 January 1272|
|Died||6 December 1311(aged 39)|
|Title||Regent of the Kamakura shogunate|
Hōjō Sadatoki (北条 貞時, April 20, 1271 - December 6, 1311) was the ninth shikken (regent) of the Kamakura shogunate (reigned 1284 - 1301), and Tokuso (de facto ruler of Japan) from his appointment as regent until his death.
The Hōjō clan had variously defeated many rival families, leaving only the Adachi clan, with whom the Hōjōs were allies. However, a plot by Adachi Yasunari to usurp the Hōjō resulted in Sadatoki authorizing Taira Yoritsuna to attack the Adachi. It is possible Taira Yoritsuna may have falsified the charges against Yasumori due to political rivalry.
The attack occurred in November 1285 and is known as the Shimotsuki (Frosty Moon) Incident. It was fought near the Adachi residence, and the Adachi were caught unaware. The fighting lasted five hours and Yasumori was forced to commit suicide, along with his family and many supporters. Over 500 died in all and the Adachi family was almost exterminated. Adachi Yasumori was Sadatoki's father's brother-in-law.
Heizen Gate Incident
Regency ends and death
Sadatoki ended his regency and entered the priesthood in 1301. Some sources claim that, although secluded in a temple, he continued to administer Japan until his death in 1311. He is