Due to Japan is surrounded by sea, there are more than 3000 lighthouses throughout Japan. The world oldest lighthouse seems to be the one in Egypt, Lighthouse of Alexandria built in BC279.
The first western style modern lighthouse in Japan was built in 1869 in Yokosuka, Kanagawa prefecture. The oldest one is Kannonzaki lighthouse which is located on Miura peninsula, the entrance to Tokyo bay.
It was the one of the eight lighthouses which Japan promised to built after the treaties signed with the United States, Great Britain, France and the Netherlands in 1866. It was built by French architect. There are still 64 lighthouses in Japan which are built during 1868 - 1912.
Lighthouses in Japan also have a function as meteorological station. These weather and maritime information can be checked on website of Japan Coast Guard which operates the lighthouses in Japan.