TOKYO -- Japanese Prime Minister Junichiro Koizumi got into the mood for the world cup with a little soccer practice in his office, Kyodo news agency reported on Wednesday. Staff was alerted by a thudding sound from the prime minister's office on Tuesday afternoon, but on making checks they found Koizumi alone with a soccer ball. "I just kicked a ball. It was not real practice," Koizumi told reporters at his residence in the evening, the agency said. The prime minister will be testing his soccer skills on Wednesday when he kicks a ball as part of the opening ceremony for a world cup warm-up match between Japan and Costa Rica, to be held in Yokohama, near Tokyo, Reuters reported.