Why did Japan expand into Korea and Manchuria during the early 1900s?

apan as a have-not country felt the distribution of natural resources in the world was unfair and in Manchuria and China proper saw its opportunity to right the balance. The need for a larger economic base was closely linked with Japanese conceptions of coming wars, the effect of the great depression and a rise in anti-Japanese feeling in China. Japan, while making strides in Manchuria, never met its goal of economic self-sufficiency. Tied down in China by a military quagmire it had neither the time nor the surplus resources to invest in creating the self-sufficient empire it so desired.