TOKYO, May 13 - The 15 day summer main professional sumo tournament opened at the Kokugikan arena, Kuramae, here, today, with attention centered on whether grand champion Terukuni will be able to win the individual championship for the third straight season.
    Among the other powerful contenders for the crown are "yokozuna" Haguroyama and two new "ozeki" wrestlers, Yoshibayama and Kagamisato. Fighting "sekiwake" Mitsuneyama is mentioned as dark horse.
    All the major matches in the senior camp are held under lights for the first time in the traditional history of Japanese sumo.