What did Japan expect after Pearl Harbor?
So Japan expected war after Pearl Harbour, but not the right kind of war. They thought they would get time to stockpile the resources they needed and await one decisive battle, while the US slowly rebuilt their capital ships. Then, once both sides were ready, they expected one winner-take-all naval battle.
Why did Japan feel it was necessary to bomb Pearl Harbor?
Why Attack Pearl Harbor? As war was inevitable, Japans only chance was the element of surprise and to destroy Americas navy as quickly as possible. Japan wanted to move into the Dutch East Indies and Malaya to conquer territories that could provide important natural resources such as oil and rubber.