Around the time of the Great War, Zhang Zuolin had established himself as a hugely powerful warlord with influence over most of Manchuria.

He is determined to keep his Manchu army under his control and to keep Manchuria free of foreign influence.

The Japanese had tried to kill him in 1916 by throwing a bomb under his carriage, but failed; they finally succeed on June 2, 1928, when a bomb explodes under his seven-carriage train a few miles from Mukden station.