A Tokin(頭襟, ときん) is a small black box worn on the foreheads of Yamabushi – practitioners of Shugendō – or Tengu, dangerous yet protective spirits of the mountains and forests from the Japanese mythology. It is not only worn as a head decoration, but also used as a drinking cup. It is similar in appearance to tefillin worn by Orthodox Jews. It is theorized that they may be of common origin (see reference articles in Japanese-Jewish Common Ancestor Theory); however the Tokin may simply be an evolution and miniaturization of a full-sized hat of the same name worn earlier in the Kamakura period.
"Tokin" is also the name of a "promoted pawn"(と金 in Japanese) in shogi (Japanese chess).