What is "yobidashi"

n. (context sumo English) the functionaries whose tasks include building the dohyo, making announcements, singing the shikona of each rikishi and advising them of preparation time

The calls a professional sumo wrestler, or rikishi, to the dohyō (wrestling ring) immediately prior to his bout. He does this by calling the name of each wrestler fighting in turn whilst holding a traditional folding fan.