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.
この絵は個人蔵のため、普段は公開されていない。
This painting is privately owned, so it is not usually open to the public.
展示品の多くは個人蔵の貴重なコレクションです。
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.