The hatred between china and japan first started In the 1930s, China was a divided country. In 1931, Japan, was eager for the vast natural resources that was in China and seeing her obvious weakness, invaded and occupied Manchuria. the Chinese Emperor who ruled it was a puppet of the Japanese. When China appealed to the League of Nations to intervene, condemned Japanese aggression. The only real consequence of this was that an outraged Japanese delegation stormed out of the League of Nations, never to return. The Japanese continued to take over china's land.