The diary revealed that Prince Takamatsu bitterly opposed the Kwantung Army's incursions in Manchuria in September 1931, the expansion of the July 1937 Marco Polo Bridge Incident into a full-scale war of aggression against China and in November 1941 warned his brother, Hirohito that the Imperial Japanese Navy could not sustain hostilities for longer than two years against the United States. He urged Emperor Shōwa to seek peace after the Japanese naval defeat at the Battle of Midway in 1942; an intervention which apparently caused a severe rift between the brothers.