Passage: Following a long record of instigating localised conflicts throughout the 1930s, Japan began a full-scale invasion of China on 7 July 1937. On 12 September, the Chinese representative, Wellington Koo, appealed to the League for international intervention. Western countries were sympathetic to the Chinese in their struggle, particularly in their stubborn defence of Shanghai, a city with a substantial number of foreigners. The League was unable to provide any practical measures; on 4 October, it turned the case over to the Nine Power Treaty Conference.

Question: When did Japan invade China?
7 July 1937