Why did Japan invade China in 1937?

thank you so much
=]

2 answers

The war was the result of a decades-long Japanese imperialist policy aiming to dominate China politically and militarily to secure its vast raw material reserves and other resources. At the same time, the rising tide of Chinese nationalism and notions of self determination made the war inevitable
The above sentences are from this article:

http://en.wikipedia.org/wiki/Second_Sino-Japanese_War