In 1937, while running errands for a construction firm, Tanaka ran into an elevator occupied by the Viscount Masatoshi Ōkōchi, head of the Riken corporation.
The drafting office only kept Tanaka busy for two years: he was drafted into the army in 1939 and sent to Manchuria, where he served as an enlisted clerk in the Morioka Cavalry, reaching the rank of senior private (jōtōhei) in March 1940.