There was an old HBO movie called Fatherland which is about the US winning the war with Japan, but losing to Germany. But I would like to talk about the opposite.

Let's say we beat Germany exactly like we did. For some reason, we don't use "The Bomb" on Japan, and we just invade them. One million die, and we retreat. What would happen next? What would happen in the immediate years, like the 50's and 60's? What would the world look like today? How long would the ground war have lasted? 10 years? More?

Edit: Please folks, the purpose of this thread is to solely talk about what would happen if Japan had repelled a potential US invasion. Please don't make comments like "There is no way they could have won" or "They would have surrendered after the invasion." Remember, on paper it looked like there was no way we would not prevail in Vietnam.

Second edit: I'm sorry for not being more clear. I'm only talking about had they successfully repelled a US invasion, not if they attacked the US mainland.