The 1930s saw Japan's invasion of mainland Asia and increased military activity in Europe. Ueshiba was concerned about the prospect of war, and became involved in a number of efforts to try and forestall the conflict that would eventually become World War II. He was part of a group, along with Shūmei Ōkawa and several wealthy Japanese backers, that tried to broker a deal with Harry Chandler to export aviation fuel from the United States to Japan (in contravention of the ), although this effort ultimately failed. In 1941 Ueshiba also undertook a secret diplomatic mission to China at the behest of Prince Fumimaro Konoe. The intended goal was a meeting with Chiang Kai-shek to establish peace talks, but Ueshiba was unable to meet with the Chinese leader, arriving too late to fulfil his mission.