Sentence:  A <WSD>"yokozuna</WSD>" is the very highest rank in sumo – “just like Mameha's position in Gion,” as Nobu explained it to me. I had no reason to doubt him; but if Mameha ever took half as much time entering a party as these "yokozuna" took entering the ring, she'd certainly never be invited back. 
Meaning of the word marked with <WSD> tags:  The highest rank of sumo wrestler, above ozeki; grand champion.