After World War II, Nosaka's return to Japan was facilitated by
E. Herbert Norman, the Canadian representative to the
Supreme Commander of the Allied Powers, who may also have been a Soviet spy. Before returning to Japan, Nosaka gained Stalin's endorsement for the leadership of the Japanese Communist Party. Nosaka's re-entry to Japan was also aided by the American diplomat
John S. Service, who had a history of being friendly to Chinese Communists. Before returning to Japan, Nosaka advised
Joseph Stalin to retain the position of the
Japanese Emperor, but to replace Emperor
Hirohito with Crown Prince
Akihito if the Communists ever gained control of Japan. After the war, Nosaka made a months-long trek from Yenan to Japan, accompanied by members of the
Japanese Peasants' and Workers' School. He traveled through
Manchuria,
North and
South Korea on foot, horseback, ox-cart, truck, plane, ship, and train. While staying in Pyongyang he met
Kim Il Sung. Nosaka arrived back in Japan in January 1946, and received a hero's welcome from the JCP. It was reported that Nosaka's arrival at party headquarters in Tokyo was treated like a celebrity event. With one newspaper reporting of young girls in both kimonos and Western dress gathered like fans awaiting a star at the stage door. In his first public address, Nosaka lambasted "so-called patriots" for destroying the nation and declared that "we Communists are the true patriots and true service brigade of democracy.". US Secretary of State
Cordell Hull had sent a cable to the American Embassy in Chungking. Where he appproved the use of Nosaka Sanzo as a "
Tito of Japan". He returned to China as a recognized protege of
Mao Zedong, and enjoyed the informal recognition as a "roving ambassador" for Japanese communism. After his return to Japan, Nosaka worked to organize Japanese communists. Nosaka's strategy was to foster what he called a "lovable" image for the JCP, seeking to take advantage of the seemingly pro-labor American-led Occupation to bring about a peaceful socialist revolution in Japan. This strategy was highly successful at first, attracting for the party a large following within the student and labor movements and among intellectuals. In the
general elections of 1946, Nosaka and four other members of the JCP were elected to the
Diet, and the party received 4% of the popular vote. Thereafter, the JCP made further progress infiltrating Japanese labor associations and socialist parties, and in the
general elections of 1949, the JCP gained 10% of the popular vote. However, with the fall of China in 1949 and increasing
Cold War tensions around the world, the United States initiated the so-called "
Reverse Course" in Occupation policy, shifting away from demilitarization and democratization to remilitarization, suppressing leftists, and strengthening Japan's conservative elements in support of U.S. Cold War objectives in Asia. At the Occupation's urging, the Japanese state and private corporations carried out a sweeping "
Red Purge", firing tens of thousands of communists and suspected communists from their jobs in both government and the private sector. In January 1950, in response to the Occupation-backed Red Purge and at the behest of Stalin, the Soviet-led
Cominform published a tract harshly criticizing the JCP's peaceful line as "opportunism" and "glorifying American imperialism" and demanding that the JCP take steps to pursue immediate violent revolution in Japan. Competition between JCP factions to win Cominform approval in the wake of this devastating "Cominform Criticism" ultimately led by the summer of 1951 to a complete reversal in JCP tactics from the peaceful pursuit of revolution within democratic institutions to an embrace of immediate and violent revolution along Maoist lines. This resulted in a campaign of terror in which JCP activists threw
Molotov cocktails at police boxes across Japan and cadres were sent into the countryside with instructions to organize oppressed farmers into "
mountain village guerrilla units" (
sanson kōsakutai). As punishment for his advocacy of the "lovable" image, Nosaka was temporarily driven out of the party and forced to go underground. After Nosaka went underground, the U.S.
Central Intelligence Agency reported that he temporarily returned to China. Meanwhile, the JCP's new militant line was a disaster. A full-blown communist revolution failed to emerge in Japan, the JCP activists were rapidly arrested and imprisoned, and in the
1952 general election, the JCP was wiped out in the polls, losing every one of the 35 seats it held in the Lower House of the
Japanese Diet. The JCP spent the next three years gradually backing down from the militant line, finally renouncing it fully in 1955, which paved the way for Nosaka's return to power. Nosaka re-emerged in Japan in 1955 as the First Secretary of the JCP. Nosaka was briefly arrested after he resurfaced, but quickly released. In 1958, Nosaka became the chairman of the JCP's Central Committee. He played a part in organizing the
Anpo protests in 1960 against the revised
US-Japan Security Treaty. In May 1960, as the protests were reaching their height, Nosaka published a lengthy essay in the Communist journal ''Zen'ei'' titled "We Will Not Accept the New Security Treaty." These massive demonstrations forced the American president,
Dwight Eisenhower, to cancel a visit to Japan, and forced the Japanese Premier,
Nobusuke Kishi, to resign, but failed to achieve their main goal of preventing passage of the revised Security Treaty, which Kishi ruthlessly rammed through the Diet in spite of the popular opposition. In Japanese public opinion, the demonstrations were received as a national embarrassment, and the JCP received only 3% of the popular vote in the
1960 elections. The Anpo protests outraged and energized the Japanese right wing. On October 12, during a televised election debate,
Inejirō Asanuma, the chairman of the
Japanese Socialist Party, was assassinated by a 17-year-old right-wing youth,
Otoya Yamaguchi, who rushed onto the stage and fatally stabbed him twice in the stomach with a
wakizashi. After his arrest, Yamaguchi told police that he had hoped to assassinate Nosaka as well. On November 13, 1963, Nosaka survived an assassination attempt while making a speech in Osaka. The perpetrator was 22-year-old Masahiro Nakao, a member of the rightist group Dai Nippon Gokuku Dan. Nakao, armed with a dagger, leaped on a platform where Nosaka was giving his speech. Nakao was subdued by Party members who turned him over to the police. Nosaka attempted to keep the JCP neutral during the
Sino-Soviet Split of the 1960s, though the CIA interpreted that Nosaka's party remained somewhat more friendly with the Chinese. On Nosaka's seventieth birthday party in 1962, Nosaka received extravagant praise from Beijing.
Deng Xiaoping praised Nosaka as an "outstanding fighter of the Japanese people and comrade-in-arms of the Chinese people". The Soviets sent Nosaka a matter-of-fact confirmation of his status within the JCP, and within a month sent the JCP another letter scolding the Party for not adequately supporting Soviet positions. The Soviets' measured praise of Nosaka was consistent with earlier
Cominform criticism of Nosaka's political theories, which advocated a peaceful transition into communism. After his re-entry into public life in 1955, Nosaka was elected to the
House of Councillors, a post that he held until 1977. Nosaka joined the faculty of
Keio University, and was one of many prominent communist intellectuals active in Japanese academic institutions in his time. Nosaka remained the JCP's chairman from 1958 to 1982, when he stepped down at the age of 90 and took the role of "Honorary Chairman". ==Scandal==