Shigeuji, however, came into conflict with the Uesugi clan, who served as Kanto-Kanrei (Governor General of Kanto), and he fled Kamakura, relocating to Koga in the Province of Shimousa and assuming the title, Koga Kubo.
しかし成氏は関東管領の上杉氏と対立し、鎌倉を放棄して下総国古河に移って古河公方と称した。