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.