The japanese are seemingly everywhere, and it's air power that allows them to be. The distance between los angeles and new york is about 27 hundred or 28 miles. This battlefield is more like six thousand miles by forty 500 miles. For some people, the pacific is the worst of all possible battlefield conditions. And if before you've solved that chaos, the planes come back and do it again.
Japan's rising sun goes supernova and engulfs a huge area of Asia and the Pacific. A war without mercy begins to develop infusing the whole conflict with a savage vibe.