The documents detail efforts by the wartime Japanese government to trivialize the discovery of the Sorge spy ring, which was at the heart of modern Japan’s biggest spy scandal. Thirty-five people, many of them highly placed Japanese officials, were arrested in Tokyo in October of 1941 for spying for the Soviet Union. Sorge, the German head of the spy ring, had fought for the Central Powers in World War I, but had subsequently become a communist and trained in espionage by Soviet military intelligence. He was then sent to Tokyo where he struck a close friendship with the German Ambassador and joined the German embassy. He eventually informed Moscow that German ally Japan was not planning to invade Russia from the east. That tip allowed Stalin to move hundreds of thousands of troops from the Far East to the German front, which in turn helped the USSR beat back the Nazi advance and win the war.

Japanese newspaper Mainichi Shimbun, which has seen the declassified documents, said they were among the personal files of Taizo Ota, a Japanese counterintelligence official who led Division VI of Japan’s Ministry of Justice. The unit was in charge of political policing and counterespionage during World War II. The documents date from May 1942, which was when the Japanese government finally publicized the arrest of Sorge and his comrades, more than six months after they were caught spying for Moscow. The documents were issued by Japan’s Ministry of Justice but —according to experts— were most likely authored by officials in Japan’s Ministry of Foreign Affairs, who were in charge of investigating the Sorge spy ring case. According to Mainichi Shimbun, the documents were part of a broader effort by the Japanese government to cover up the espionage case by instructing the country’s media to give it marginal attention.

One document instructs newspaper editors to cover the incident on an inside page and to use a headline smaller than the length of four columns. Another document states that newspaper editors should not use pictures in reporting on the spy ring, and adds that no information other than what is included in government press releases should be printed. A third document specifically instructs newspaper editors to avoid all mention of Kinkazu Saionji, a core participant in the Sorge spy ring. Saionji was a member of Japan’s governing aristocracy and a grandson of former Prime Minister Kinmochi Saionji, the country’s most esteemed interwar politician. Indeed, much of the information in the newly unearthed documents details efforts by the Japanese state to conceal the magnitude of communist penetration in the country’s leading families and governing circles.

Coverage of the Sorge incident in Japan’s two leading newspapers of the time, the Nichi Shimbunand the Asahi Shimbun indicate that the government pressure was successful, according to Mainichi Shimbun. Both papers covered the incident but neither paper published information about it on its front page, nor was there mention of Saionji or of other senior Japanese officials who were members of the Sorge spy ring. According to Japanese researchers, the documents provide rare detailed examples of attempts by the country’s wartime government to guide reporting on national-security affairs. The files are currently archived in the Modern Japanese Political History Materials Room of the National Diet Library in downtown Tokyo.