Why blockading Japan differed from blockading Germany

Germany's railways, canals, roads, and land borders complicated a blockade because sea routes formed only part of its supply network. Cutting the Baltic route would also have denied it supplies from Sweden and other Scandinavian countries. Japan's island geography left more of its transport dependent on maritime routes. The proposed British close blockade used submarines and mines to attack that traffic. Cruisers could threaten the escorts protecting Japanese shipping, with the battle fleet covering the operation if Japan's fleet intervened. On that reasoning, a blockade did not have to await a decisive battle between the opposing fleets.