Sumo's longest-serving yokozuna Hakuho retired on Thursday when the Japan Sumo Association's board of directors accepted his request to end a 20-year competitive career in Japan's ancient sport.The Mongolian-born grand champion, winner of a record 45 grand sumo tournaments, has been dogged by injury the past few years and had surgery on his right knee in March. For the time being, he will serve as an instructor with his Miyagino stable as sumo elder Magaki.The 36-year-old has been ranked as yokozuna for 84 tournaments, or about 14 years. His 45 titles in the top makuuchi division are more t…READ FULL ARTICLE