If Chi Buzhou made a courageous and patriotic decision to return to China in 1937, he made the wrong judgment to remain in 1949.
After the establishment of the new state, he worked in a savings branch of the People's Bank in Shanghai. In 1951, the government launched a campaign against 'counter-revolutionaries' and Chi was arrested. With his background in one of the Nationalist government's most important intelligence units, he was an obvious target.
In January 1952, a military court in Shanghai sentenced him to 12 years in prison and he started his sentence as an accountant in a factory inside a labour reform camp.
In 1956, he was sent to 'study' at camps run by the PLA in Shandong and only returned to Shanghai in 1963. In 1979, he was invited to work at the Shanghai Academy of Social Sciences, where he researched the economic history of Taiwan. Finally, in March 1983, two of his wartime colleagues testified that he was not a criminal, had not worked as a spy and had made an important contribution in the war against Japan. In April that year - more than 30 years after the original accusation - the Shanghai High People's Court said Chi was innocent and he became a CPPCC member for the city's Changning district.
He later returned with his wife to Japan for his final years and taught at Kobe university. He died in February 2003, at 94. His ashes were brought back to China after his death.
In his memoirs, he was modest about his contribution. 'The young people of my generation took part in the war against Japan, at a moment when our people were facing a crucial period of life or death. Everyone made whatever contribution they could.
'Breaking the Japanese codes was a significant contribution. It was not my work alone but the work of many people in different departments.'
He reflected on how militarism had wreaked so much destruction. 'China and Japan had been good neighbours for more than 2,000 years and the culture of China brought over during the Tang dynasty became the basis of Japanese civilisation. This is something everyone knows.
'After the war, the Japanese government learnt from its past mistakes and built a new country based on peace, democracy and law. It concentrated on construction and built an economic superpower. A new era of Sino-Japanese friendship has arrived, with a conviction deep in every generation that they can never make war again.'