Chiba prefecture (千葉県 Chiba-ken) is located east of Tokyo, and bordered by Ibaraki prefecture to the north.
Chiba is the eponymous capital of the prefecture, which doesn't bear much resemblance to William Gibson's depictions but has a few points of interest for would-be cyberpunks.
While JR trains run the entire coast of Chiba, the inner coast is just a 30-minute ferry ride from Kurihama, south of Yokohama.