In 1213, he formed an alliance with his cousin Yoshimori WADA, the Samurai-dokoro shoshi at the time, in order to defeat the Hojo clan, but he betrayed Yoshimori at the last minute by informing Yoshitoki HOJO that Yoshimori has raised an army; consequently, Yoshimori was defeated, and the WADA clan was destroyed (Battle of WADA).
建暦3年（1213年）には従兄弟で侍所所司であった和田義盛と北条氏打倒で結ぶが、これを直前で裏切って北条義時に義盛の挙兵を告げ、義盛は敗れて和田氏は滅ぶ（和田合戦）。