” I doubt that the Japanese Navy would be much of a match for China.”
Edify yourself.
They are the 4th largest Navy by tonnage, have AEGIS Destroyers...and a great culture with naval warfare experience.
They could put 80 warships to sea on a moments notice. And follow with another 30 in 30 days. Their subs are superior.
Their Air Force can cover them from the air too.
Think of them as a Badger. While you might win, you will suffer horrible wounds and may die from them later.
When I read this I thought of electric subs. Japan must have some good ones.