Which factor most influenced japans expansion efforts in 1930s and 1940s

The biggest factor that influenced Japanese expansion in the 1930's and 1940's was the lack of resources. Japan is a country that lacks natural resources and is heavily dependent on imported resources. The country was unwilling to capitulate, so they attacked the territories that were of great use for them, like modern day Indonesia and Malaysia because of their reserves of oil, tin and rubber plantations.