The Japanese navy is a true blue water navy. They have a new class of super silent submarines and “aircraft” carriers. (Their carriers are for helicopters, but could be converted easily.)
In a war, Japan would sink everything commercial going to or coming from China whereas China would have a hard time doing the same to Japan. Where both nations need imported food, China has direct access to the Pacific and China does not, in the same way.
China is on the verge of a complete collapse and their economy is one of the worst on the planet. Not saying they aren’t crazy enough to go to war, but it would be near suicidal given their current state.
Below are some interesting articles on the situation.
China will hold itself back. War that would draw in the USA would have people rally around Trump and give him war powers. They do not want a strong, angry America lead by Trump. Maybe after he is re-elected They Might move. BUT each day they wait Japans navy gets stronger. Two points of danger. 1) When Japan launches a full aircraft carrier. 2) They change the name of the Navy to “The Imperial Japanese Navy”.