Dai-Teikokushin

[Diamond]

This area especially - you've got a lake in the center of that island, and there's either two rivers flowing into it, two flowing out, or one flowing in/one out. If it's option one, where's the egress? If it's option two, that doesn't normally happen as water will seek the easiest egress point and over time all outflow will naturally go that way. If it's option three, then you've got on branch flowing uphill from the ocean.

In addition, the branches to the south of the lake split. Normally, rivers join together as they flow towards the sea, like a tree with the main river being the trunk and the tributary rivers as branches that join the trunk. Just as when water flows out of a lake, rivers flowing downhill always seek the 'easiest' route; if something makes the river split, eventually one branch will dry up as the water seeks the easier route. There are exceptions, of course - a manmade canal or re-routing, or islands/rocks in a wide river. Deltas, where water/rivers split apart over a relatively wide area, are common when it is extremely flat, undifferentiated ground.