In June 1928, adventurist officers of the Guandong Army, the Imperial Japanese Army unit stationed in Manchuria, embarked an unauthorized initiatives to protect Japanese interests, including the assassination of a former ally, Manchurian warlord Zhang Zuolin. The perpetrators hoped the Chinese would be prompted to take military action, forcing the Guandong Army to retaliate. The Japanese high command and the Chinese, however, both refused to mobilize. The incident turned out to be a striking example of unchecked terrorism. Even though press censorship kept the Japanese public from knowing about these events, they led to the downfall of Tanaka and set the stage for a similar plot, the Manchurian Incident, in 1931.