The retired Emperor Go-Saga, who started a cloister government, left a will for the brother of the retired Emperor Go-Fukakusa, Emperor Kameyama's descendant (Daikakuji-to), to succeed to the Imperial Throne, and this caused the mutual conflict; therefore, it was decided by the Kamakura shogunate to share the Imperial Throne between ancestors from both sides on the basis of a rotation every 10 years (Ryoto Teiritsu) and to continue running the cloister government.
院政を敷いた後嵯峨上皇が、後深草上皇の弟亀山天皇の子孫（大覚寺統）が皇位を継承するよう遺言して崩御したために、後深草と亀山の間で対立が起こり、鎌倉幕府により、両者の子孫の間でほぼ十年をめどに交互に皇位を継承（両統迭立）し、院政を行うよう裁定された。