Why did Japan invade Manchuria and Korea?

If I remember this correctly, this happened in the beginning of WW2. Imperial Japan at the time really wanted more land, for their highly developed industry, and they needed more land for more natural resources. So they invaded Manchuria and Korea for things like oil, rubber, and lumber.

On the night of 18 September 1931, an explosion on a section of South Manchuria Railway, giving the Japanese army the excuse it needed to blame the local government, and toke control of the nearest Manchurian town of Shenyang

Explanation:

The league of China immediately requests the Japanese army to withdraw.