TOKYO, Jan. 18 - Masuiyama, new "ozeki" of the East team, who had been maintaining an undefeated record until the sixth day, lost to Rikidozan, "komusubi," on the seventh day of the 13 day spring professional sumo tournament at the temporary Kokugikan in Hama-cho Park here today.
    As the result of Masuiyama's defeat, Kuninobori, "maegashira" of the East team, is now the only undefeated wrestler in the senior camp. He pushed out Kotonishiki on the seventh day.
    Three of the four "yokozuna" grapplers - Haguroyama, Terukuni and Maedayama - are not participating in the current tournament.