Answer:
The Mukden Incident was a train sabotage on 18 September 1931 in southwest Manchuria, when Japanese military personnel blew up a section of the Japan-owned southern railway near the city of Mukden, now Shenyang.
The Japanese imperial army accused Chinese dissidents of the act of sabotage and the event was used as a pretext for the Japanese invasion and annexation of Manchuria.
The incident represented one of the earliest milestones of the Second Sino-Japanese War, which later merged with the conflicts in Europe that started World War II.