英Wikiのこのページの「4.Supply and attrition」のところに書いてある -- 2020-03-28 (土) 01:56:19
包囲時のはAttrition damageに書いてある「Besieging armies will always take at least 1% base Attrition attrition, even if the province is unfortified. This rule only applies to enemy-owned provinces, however - when besieging friendly provinces to retake them from the enemy, this rule is ignored.」。それ以外も知りたければその周辺も読んでみて -- 2020-03-28 (土) 01:58:51