On a practical level they were useful for preventing draughts and preserving the privacy of its owner. Their carefully thought-out design was not purely decorative: the motifs were often chosen to provide an intellectual stimulus for a writer or painter.
A 19th century example, measuring 11 x 12 x 6in (28 x 30 x 15cm), is coming up in Schuler’s auction on December 7-11 in Zurich with an estimate of SFr1200-1800.
The wooden frame holds a central panel with inlays of mother-of-pearl, bone, soapstone and semi-precious stones and is decorated with three crabs among reeds. Crabs are a symbol of harmony or peace and can be found on water dishes or ink blocks and other implements connected to Chinese scholarship.