O-Beshimi (large clenched mouth): a mask worn by powerful deities and demons. Here the gold eyes, and red color of the skin indicate terrifying power; the clenched mouth indicates that that power is kept under close control. Both this mask and the O-Tobide mask are based on the features of guardian deity statues found at the gates of Buddhist temples. These temple guardians were thought to have originally been ferocious local gods who had converted to Buddhism, and now use their power to defend Buddhism.

The name of this mask is also used to describe a kind of exageratedly grimacing face, with eyes rolled back into the head, commonly used in the contemporary Japanese dance form Butoh, (although in fact, the O-Tobide mask might be a better fit). See below, for two examples of beshimi in Butoh:

This image is from the Dairakudakan webpage: http://www.geocities.co.jp/Hollywood-Stage/8138/rakudakan/top.html

Kudo Taketeru and Motofuji Akiko, Kamakura 1996

Photo: Kevin Bubriski

Source: http://www.sover.net/~bubriski/butoh/butoh11.html