How do we know the war is coming in the first place? Because the advertising for it is out. Amongst plenty of other evidence, one Chinese front organisation conducted a poll on Australian attitudes to the ANZUS treaty and a Chinese attack on Japan. Why would they conduct such a poll unless they are going to attack Japan? Not that they were interested in the results as such. They just wanted to be able to publicize the poll in order to try to keep Australia on the sidelines of their war.