This game sounds hard
Japanese aristocrats during the Heian Period (794-1185) developed a game of matching using beautifully-painted clamshells. Called kai-awase, or “shell matching,” it was popular chiefly among women and children.
The artist polished the outside of the clam halves and painted intricate, identical scenes on the insides.
To check whether a player had correctly chosen a match, she would try to put the two parts of the shell together. If they fit, and the paintings on the inner portions were identical, then she won the shell.
Japanese nobility stored their games in elaborate containers. During the Edo or Tokugawa period (1603-1868), the sets were often given as part of a woman’s dowry. Receiving a kai-awase as a marriage gift was considered good luck, as the joining of clams symbolized the joining of a wife and husband in marriage.
Today, the tradition is not forgotten. The miniature paintings of Ogoshi Kimiko are a testament to its continued cultural and artistic influence:
And if you’re interested in buying some kai-awase shells, I found this beautiful set for sale on Ebay:
Via Liza Dalby