Mines.
If you look at WWI and WWII the number of ships sunk per mines laid is astonishingly high.
And since 1950, of the 19 USN ships destroyed or damaged, 14 of them were by mines.
Ask yourself these questions:
1) How much mine-clearing capacity does the PRC have?
2) How much mine-clearing experience do they have?
3) What happens when every PRC commercial and military port gets mined?
For fun, ask the same question pointed the other way:
1) How much mine-clearing capacity does the ROC /USA have?
2) How much mine-clearing experience do they have?
3) What happens when every US commercial and military port gets mined?
Bonus question:
Where are all us minesweepers homeported, what is there maximum speed, and how loing would it take them to arrive at and clear the port of LA, New York, etc.
Not to mention, the mining of Haiphong harbor did more to end the VietNam hostilities than any other single intervention.
I am surprised that wargaming of an attack on Taiwan omits a counterattack on the Three Gorges Dam, an extremely vulnerable target and the source of 10% of the total energy generation of the entire Chinese mainland.
Ah yes, you are RIGHT : MINES. And yet they have limitations too : only useful in limited areas like ports(no one can cover the whole ocean with mines)and if they drift you could have a friendly fire sinking. Plus I’m sure there are defensive measures that can be taken against floating or submerged mines, WW II was 60 years ago, marine technology/development didn’t STOP when it did.
Be as it may, how versed in marine transportation are you? I’d like to run a few ideas by you, in a private post.