Or okame. Literally 'Great luck'. A mask of a woman's round smiling face with flat nose used to bring luck. She is identified with the kami Ame-no-ozume.
See Muneage. An otafuku is often paired with saruda-hiko or with a hyottoko (written hi=fire and otoko=man) mask, a comic mask of a man's face with one small and one normal sized eye, sometimes a beard or moustache and lips pursed, perhaps to breathe fire.
A Popular Dictionary of Shinto. Brian Bocking.