Port problems in India and Japan:
A province cannot have sea trade with a neighbouring province, neighbouring provinces do landtrade. If the Hokyo province would stretch to the sea and divide the Yuusen and Akagi provinces, Yuusen should be able to trade with Akagi. Same goes with the indian provinces.

Suggestion:
It would be helpful to add more, but smaller coastal provinces to prevent those "dead" ports and give the trade AI more possibilities to choose from - this also means some more cities to conquer.