As hostilities between Japan and China escalated, Sorge reported back to Moscow about the readiness of CHinese troops and their chances against a superior Japanes military. After Ozaki returned to Japan in 1932, Sorge fell under suspicion of being a spy. He therefore poured himself into his work as a journalist for almost a year.His writing appealed to members of Chang Kai-shek's military circle, who conferred with Sorge, thus unknowingly providing him with valuable information. he was identified as likely being an agent for Germany.

Sorge was recalled to Moscow in 1932 and met with great praise from his Soviet handlers. While in Russia he married a woman named Yekaterina Maximova. Soon thereafterhe was dispatched to Japan. Because of his excellent work product in China, his Soviet superiors felt that he might be the only agent that could obtain intelligence information in Japan which was at that time extremely secure against information leaks. He was assigned to determine whether Japan was prepared to move militarily against China, with a primary goal of determining the feasibility of developing a Soviet spy network in Japan.

Codenamed "Ramsey", Sorge went to Germany and obtained a German passport. Traveling as a German journalist, he arrived in Japan in September 1933. His spy cell was limited to himself and three other people in order to provide for maximum secrecy. He worked with Branko Vukelic, Yotoku Miyagi and a radio operator named Bernhardt. He immediately found that Benrhardt was a heavy drinker, a liability in that he was often too impaired to transmit his radio messages. In fact, at one point Sorge discovered that nearly half of his messages had not been transmitted by Bernhardt. Bernhardt was soon thereafter recalled to Moscow. Vukelic was quite adept at photographing documents obtained by Sorge and Sorge received information from Miiyagi, courtesy of Sorge's old contact Ozaki.