Port city on southern honshu island?
Fuji is a city, at the foot of Mt Fuji, in the Honshu region of Japan in the eastern and southern hemisphere. Japan is not in the Southern Hemisphere but in the Northern Hemisphere. However, if the questioner meant Fiji Island in the South Pacific, it is in the Southern Hemisphere [ and in the Eastern Hemisphere].
Yokosuka is a name of the city in Kanagawa Prefecture in a part of Honshu, and Kanagawa Prefecture is located in Honshu. Japan is an arc-shaped archipelago consisting of four main islands, Hokkaido, Honshu, Shikoku, and Kyushu, and there are, in total, more than 6,000 islands. The largest island is called Honshu.