TOKYO, May 22 - Hefty Haguroyama, grand champion in Japan's sumodom, keeping his winning streak since the opening day of the current professional sumo tournament, was the only undefeated wrestler among four "yokozuna" grapplers including Azumafuji, Terukuni and Maedayama at the end of the seventh day of the 15 day tourney at the Kokugikan in Hamacho park here yesterday.
    Two other wrestlers in the senior camp - Mitsuneyama, "ozeki," and Tsunenoyama, "maegashira" - are also maintaining their undefeated record in the competition.