They were out already in HOI3
Another thing from Da9l's WWW as Japan is that if you land and can grab enough land to gain 51% of a state/area, you're able to use the supply from the state. That probably isn't going to be enough to launch a major offensive from there or anything, but it could make it enough for the invader to be really difficult to be pushed out. With some of the smaller states/areas this might be a quick thing that will let you be more leisurely about the taking of the ports to get the full supply in.
^thatIt's easy: kill the landing force.
Is it true that EVERY coastal pronvice can be invaded by sea.
The beaches are removed?
I domt like it