You should read more Japanese media and listen to actual Japanese people's interview about China. There are many out there on Youtube. For Japanese people, Chinese are unclean, dirty, unorganized and foolish. They are also completely mindless drones controlled by the CCP. Interestingly in the US, african-american people have the same stereotype in the eyes of the white majority.First of all, that's not my question. My question was how Japan feels seeing the US fall from a country that boasts its unequivocal power and ability to protect its allies from their enemies to one that says it needs others to protect it from China.
Secondly, I don't think the Japanese feel the way you think at all. Japanese are characterized by insecure feelings, which is expected from a country that was defeated and militarily occupied. They may feel that the Chinese are rude and sometimes dirty, but they are under no illusion that the Chinese are inferior in any meaningful area such as intellect or innovative capacity. Before China's boom, they may have felt that way but Japanese are not a stupid people and they see the modern events happening today. They know that no country that can put the US on its back feet and into a panic can be an inferior people to anyone. Fear is their main emotion when dealing with China and one cannot fear something without respecting it.
I do not believe in any permanent bonds in international relations. Japan and Australia may side with the US when they perceive it to be the winning side but when China is in a place where the US cannot win, they will move over to China's side for the sake of survival. For Japan, it will be especially easy to get its population to hate the people that dropped 2 nuclear weapons on it an militarily occupied it for decades.
Who else thinks that away about the Chinese? Taiwanese, South Koreans and Hong Kongers. You see a pattern here? Every country or region that were controlled by the west and who gained their wealth by being subordinate to the west consider Chinese to be inferior as people.
When people have such racist thinking about another people. They will do anything to prevent the so called inferior people to be in a position of dominance over them. Even if it is suicidal. Look at Hong kongers, China had absolute dominance in Hong Kong. But that didn't prevent Hong kongers from having the delusion that all they have to do is do huge violent protest and Chinese government would surrender to their demands. That China will be afraid of the Western sanctions or Somehow US will send their carriers to save them. They came up delusional ideas to inspire their people to fight against China.
I believe Japanese and Australians will be equally fanatical to fight China. Even if US is out of the picture they will become absolute fortresses like North Korea just to prevent China from having any kind of dominance over them.