Let's say in a scenario akin to TL-191, where the the CSA wins the American Civil War and the US is permanently divided half (so unlike TL 191, the CSA is not reabsorbed into the US at a much later date). Japan, like OTL and in TL 191, builds it's empire anyways roughly along the borders of its OTL maximum extent in WWII. In this scenario, with the US not an existential threat to the Japanese Empire, how would the Japanese empire fare? Would it be bogged down in a perpetual war in China? Would it eventually become a pacific Superpower? And would it be able to invade Australia, either during its war of conquest or decades afters it's initial conquest war when it would've consolidated its gains elsewhere.