

(1) Oddly enough, the coring range corresponds to the colonial range. That way you can have a vassal, feed it with some provinces, and annex it later on, which will give you cores on those provinces at no admin cost (it will cost you diplo points for annexing though). I'd personally go for option 1 if you can (I can't check if there's any nation you can release in that area).

If you are at the begining of the game, Brandenburg and Teutonic Order do not have adjencent provinces. You can check the coring range using the Colonial map mode. Non-cored province must be in coring range.You must have a cored province with a port."In coring range" includes the following aspects: In order to be able to core a province, said province needs to be adjecent to, or be in coring range, one of your core provinces.
