Unlike the usual characteristics of Japanese mountain castles, in which they had residences at the foot of mountains for their convenience and had facilities for combat and defense on mountaintops, the Kannonji-jo Castle had Kuruwa, which were like areas for residential complexes, comfortable to live in, throughout the entire area of the foot of the mountain, which is the biggest difference between other mountain castles in Japan.
山城の特徴として、居住に便利なように山麓に居館を設け、山上付近に戦闘、防備施設があるのが一般的だが、観音寺城は山麓全体に分譲地、もしくは団地のような居住性の高い曲輪が配されている点が他の山城とは大きく異なる。