TOKYO, Dec. 24 - On almost every vacant lot in the scarred country, Japanese of all ages are busily engaged in forwarding a new enthusiasm for sports, and particularly their favorite baseball.
    It is American Baseball.
    Imported whole from the States, baseball has swept virtually every corner of this country. It helps the people forget a black past.
    It is more popular even than the sport in which the Japanese excel - swimming. But they are bombastically proud of stocky Hironoshin Furuhashi, who really brought them back to international athletic attention. He set three world's records in a spectacular performance at the AAU swimming championships in Los Angeles last August.
    Half a dozen other sports, all imported from abroad, have found new post-war popularity among the vigorous Japanese. Before the war, they were familiar with such games as American football, rugby, soccer, field, tennis and golf. Most of these sports withered and some died during the martial period.
    Now, in peacetime, most of the purely native Japanese sports have been outlawed by occupation authorities or permitted only on a small scale, because they are considered too militaristic. In this category are judo (jiu jitsu), a form of sly and dangerous wrestling, kendo, a style of fencing on the pattern of ancient two-sword warriors, karate, a type of strong-arm performance with toughened hands which was sometimes fatal.