共とも箱ばこ

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.

• この茶ちゃ碗わんは共とも箱ばこが付ついているので価か値ちが高たかい。

  This tea bowl comes with its original signed box, so it is highly valued.

• 共とも箱ばこがあると作さく品ひんの真しん贋がんの判はん断だん材ざい料りょうになる。

  Having the original signed box helps determine the authenticity of the work.