TOKYO (UP) - Japanese Sumo, the sport of freak Japanese giants, will soon enjoy the ''golden era" that featured unfailing sellouts at arenas in the prewar days.
    In the doldrums in the last couple ears of the war and the immediate postwar years, the sport has staged a remarkable comeback within the past 18 months. Daily sellouts, with crowds exceeding the 20,000 mark featured the last "summer" championship 15-day meet in Tokyo in May.
    The promotion of 24-year-old Chiyonoyama, a 250-pound giant hailing from Hokkaido, northernmost island - winner of the May tournament with 14 victories and one defeat - to the rank of Yokozuna" - a grand champion - will bring a "Golden era" in the sport in the opinion of Sumo experts.
    THEY POINT that the next tourney in January - the "spring" championships - will feature the presence of four grand champions. The others are 350-pound Azumafuji, 325-pound Terukuni and 300-pound Haguroyama. Chiyonoyama was the 41st wrestler to be named a Yokozuna in Japanese Sumo annals.
    Once a wrestler becomes a grand champion, he will not be demoted in contrast to the others whose rankings depends upon their showing in the tourneys. But if he loses a bit too much in the opinion of the Sumo directors, a Yokozuna will be forced to retire lest this rank suffer loss of prestige.
    Directors of the Japan Sumo Association are building their hopes for several continuous years of record gates on Chiyonoyama, who would make a sterling tackle for any American professional football team. He is over 6 feet tall, weighs 250 pounds and is all muscle. He has powerful arms and his favorite winning trick is to shove his opponents out of the ring. (In Sumo, a wrestler is defeated the moment any part of his body with the exception of the foot touches the ground or when he is out of a straw-made ring.)
    THE DIRECTORS think Chiyonoyama will be a second "Futabayama" - a grand champion who scored 69 continuous victories and was invincible over a period of several years. The fans turned out enmasse in the hope to seeing someone defeat him.
    To become a "real champion" as firm as the rock of Gibraltar, Chiyonoyama will now concentrate on trying to develop a great belly and thereby increase his weight to as near the 400-pound mark as he can. A protruding belly would be a handicap in any sport but in Sumo it is a tremendous asset. A wrestler uses it as a lever to lift his opponent into the air and then deposit him outside of the ring for victory.
    Undoubtedly, Chiyonoyama is going to eat a lot rice and drink a lot of beer to get that belly. And he will not find it too difficult for Japan's economic situation has improved and there is plenty of food available today.