noun which may take the genitive case particle 'no', noun
privately owned; in a private collection
Used especially for artworks, antiques, or valuable items that belong to an individual rather than a museum or institution. Often appears in catalogues or exhibition notes.
This painting is privately owned, so it is not usually open to the public.
Many of the exhibits are from a valuable private collection.
所蔵 means 'in the possession of' and is used for both institutions and individuals; 個人蔵 explicitly marks the owner as a private individual.
Compound of 個人 (individual) and 蔵 (storehouse, collection). The term follows standard Sino-Japanese word formation.