During the time of the regent Tokimune HOJO, Japan was twice invaded by the Mongols, and although the Kamakura bakufu managed to repel both invasions, it was an international conflict and thus there was no enemy land to confiscate and award to their soldiers, leaving them unable to provide suitable rewards, something that only strengthened malcontent among the warrior class.
執権北条時宗の代に2度に渡る元寇があり、鎌倉幕府はこれを撃退したが、他国との戦役であり新たに領土を得たわけではなかったため、十分な恩賞を与えることができず、これもまた武士たちの不満を強めさせた。