1939 Japanese expedition to Tibet
The Japanese expedition to Tibet was an intelligence mission undertaken by Jinzō Nomoto (野本 甚蔵, Nomoto Jinzō) in Tibet in 1939. == Background == From 1918 to 1922, Japan began conducting secret operations in the Xinjiang area.
Source: Wikipedia — 1939 Japanese expedition to Tibet (CC BY-SA 4.0)