Emperor Juntoku enthusiastically supported the plan to overthrow the shogunate, so in 1221, he abdicated in favor of Imperial Prince Kanenari (who became Emperor Chukyo), and with his newfound freedom from official duties he actively worked to aid the plan to topple the shogunate.
順徳天皇は討幕に積極的で、承久3年（1221年）に懐成親王（仲恭天皇）に譲位し、自由な立場になって積極的に協力する。