In 1187, when MINAMOTO no Yoritomo visited Hakone gongen (sacred mountain) to pray, Hakoomaru found his enemy Suketsune KUDO was accompanying Yoritomo, and chased him in order to get revenge, but rather than defeating his enemy was instead admonished by Suketsune and condemned to Akagie no Tanto 'short sword with bishop wood shaft' (Goro Tokimune murdered Suketsune KUDO with this sword thereafter).
文治3年（1187年）、源頼朝が箱根権現に参拝した際、箱王丸は随参した敵の工藤祐経を見つけ、復讐しようと付けねらうが、敵を討つどころか逆に祐経に諭されて「赤木柄の短刀」を授けられる（後に五郎時致は、この「赤木柄の短刀」で工藤祐経に止めをさした）。