a Navajo supernatural represented by a masked dancer in an initiation or curative ceremony according to Webster's ( language=Diné; pronunciation=YAY-beh-chai). "Pueblo masking influenced neighboring tribal dances such as the curative yeibichai of the Navajo." [Encyclopædia Britannica; see cue/www= britannica.com] Translates as "Nightway," a 9-day ceremony where a patient is treated for mental problems; features sandpainting in the last 4 days; 9th night climax with a drama illustrating an elaborate myth. [Dutton, Bertha P. American Indians of the Southwest. Albuquerque: University of New Mexico Press. 1983] "Yei" is the name of the gods who come masked, then are revealed at the end as only human.