Page "Geography of Japan" Paragraph 37

Extensive coastal shipping, especially around the Seto Inland Sea ( Seto Naikai ), compensates for the lack of navigable rivers.

The Pacific coastline south of Tokyo is characterized by long, narrow, gradually shallowing inlets produced by sedimentation, which has created many natural harbors.

The Pacific coastline north of Tokyo, the coast of Hokkaidō, and the Sea of Japan coast are generally unindented, with few natural harbors.