GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
The Mukden Incident in 1931 saw the invasion of Manchuria, which was a Chinese territory.It's always been my understanding that the Japanese first invaded China in 1929, but then, their feud goes back farther than that.
...however...
My quote of WWII starting in 1939 is where the publication starts...with the invasion of Poland.
Over the next six years, there were skirmishes between China and Japan, but the shooting war started in July 1937 with Japan's full-scale invasion of Chinese proper.