After graduation, Kumagai worked for the Wako Koeki trading company (和光交易株式会社),[4] which specialized in collaborating with communist countries.
In October 1980, the KGB told a Wako executive in Moscow they were looking for "a robot which builds [propeller] screws for large vessels".
[5] Wako created a connection to the Toshiba Machine Corporation (東芝機械株式会社),[6] which also specialized in collaborating with communist countries.
[7] The Itochu Corporation worked with Wako and Toshiba Machine, shifting responsibility for the violation to the other two companies in an agreement signed on April 24, 1981.
Another Itochu subsidiary, Ataka and Company (安宅産業株式会社), also worked with communist countries to export a set of three-axis machine tools.
Kumagai was charged with installing two machines in the propeller factory of Leningrad's Baltic Shipyard; the two remaining sets arrived later.
He told Wako about the illegal exports after working with communist countries for 22 years and living in Moscow for ten.
Kumagai unsuccessfully attempted to report what he knew to the Tokyo Metropolitan Police Department, but officials sided with the corporations.
Concerned about a possible assassination attempt, he recorded in detail what he knew about the Soviet Union in the spring of 1986 and gave his friend a copy for safekeeping.