On December 27, 1951, Prime Minister Yoshida Shigeru sent John F. Dulles a letter that explained 'Counter Infiltration" against China. Yoshida thought the best way to wean Chinese from the Communist regime was by sending people into China through trade activities and encouraging an anticommunist movement in China. He believed that Japan could have a major role in such an operation. The purpose of this paper is to examine Yoshida's 'Counter Infiltration" plan against China from the standpoint of intelligence. Yoshida, taking a special interest in intelligence, established intelligence organs such as the Public Security Intelligence Agency and the Cabinet Research Office (CRO) in quick succession soon after the San Francisco Peace Treaty went into effect in April 1952. Worried about indirect aggression from communist countries, Yoshida concentrated his efforts on developing an interior intelligence framework. At the same time, he tried to foster the growth of a Japanese intelligence organization that could gather information and perform covert operations in Mainland China.This study shows that Yoshida proactively tried to strengthen intelligence cooperation with governments of both Taiwan and the United States. Yoshida appointed Ogata Taketora Chief Cabinet Secretary and made him supervisor of Japanese intelligence organs. Ogata urged the Nationalist government on Taiwan to cooperate in establishing a Communist information exchange organ, and asked the U.S. Central Intelligence Agency (CIA) for assistance in creating a Japanese CIA. On the other hand, Yoshida let retired lieutenant General Tatsumi Eiichi recruit ex-military personnel for service in the CRO. With the assistance of Tatsumi, the CRO started actual intelligence activity against China after January 1953. The CRO interrogated repatriates from China, and proposed a joint operation with the CIA to send Japanese agents into Macao. Thus Yoshida tried to establish a Japanese intelligence system and backed U.S. strategy against China in the intelligence field.Yoshida's idea, however, was frustrated by rapid changes at home and abroad. After the Peace Treaty came into force, Yoshida couldn't maintain a firm hold on power. Not only the opposition parties but also the media criticized Ogata's plan to launch a Japanese CIA. In the end, Ogata had no choice but to downscale his ambitious plans, and eliminate overseas covert operations. Moreover, Yoshida's confrontational approach against the Chinese government was criticized for being behind the times after the Indochina armistice in 1954. In the last days of his ministry, Yoshida encouraged both Britain and U.S. to set up a 'high command" on China in Singapore. His aim was to use overseas Chinese based in Southeast Asia to infiltrate Mainland China, but his idea wasn't put into practice because he was unable to gain the support of either Britain and the United States or even his own entourage. [ABSTRACT FROM AUTHOR]