Because Emperor Shijo had died on February 10, 1242 at the age of only 12, a crown prince hadn't yet been selected, so the choice of a successor took considerable time.
仁治3年（1242年）1月9日(旧暦)四条天皇崩御の際、天皇は僅か12歳での崩御であった為皇太子が定まっておらず後継者選定に時間がかかった。