Most of the Gohojo clan's subsidiary castles in the Kanto area had fallen prior to Odawara Castle, which was the main castle, but even after the surrender of Odawara Castle the attack on Oshi Castle continued till early July 1590.
関東各地の後北条氏のほとんどの支城は本城である小田原城よりも先に陥落したが、忍城では小田原開城後の7月初旬まで戦闘が続いた。