The besieged army of Kumamoto Castle was helpless against the Satsuma army, which attacked the castle mainly with counterbattery activities while laying a long drawn-out siege to make the besieged army run out of the provisions and fall.
城中の糧食が尽きるのを待って陥落させるという長囲策を採る薩軍が対砲戦を主としたので、守城側はそれに苦しんだ。