noun
original signed box; creator-signed box
Refers to the original wooden box in which a piece of art (especially ceramics) is stored, bearing the artist's signature and seal. Used in contexts of art authentication and appraisal.
この茶碗は共箱が付いているので価値が高い。
This tea bowl comes with its original signed box, so it is highly valued.
共箱があると作品の真贋の判断材料になる。
Having the original signed box helps determine the authenticity of the work.