The Evolution of Communication Networks Connecting the World

The Internet is a single, global network that connects various networks together.
Users can not only send emails overseas just as they do domestically, but they can also connect to foreign websites or use generative AI with just a click. It is now common knowledge that even if a website looks like it is in Japanese, the server might be located abroad, meaning we are connecting to foreign countries without even realizing it. There, one feels absolutely no sense of national borders.

The pathways for this "communication" that connects Japan with the rest of the world are fiber-optic cables running along the ocean floor. As the exchange of information between countries increases, submarine optical cables have become an indispensable foundation for communication.

The first submarine cable was landed in Japan in 1871 (the 4th year of the Meiji era). It connected Shanghai and Nagasaki, established by the Danish Great Northern Telegraph Company.

The cable at that time was a telegraph line consisting of copper wires waterproofed with a resin called gutta-percha, and it provided only a single line. Later, in the early 20th century, wireless telegraphy was put into practical use, and shortwave radio played the leading role in communication around the time of World War II. However, in the 1950s, submarine coaxial cables that could also be used for telephone calls appeared and took over that position. Furthermore, in the late 1960s, communication via Intelsat satellites emerged, gradually surpassing cables.

Then, in the late 1980s, submarine optical cables were put into practical use, and they have remained the leading international transmission path to this day. Interestingly, if you list the transitions of international transmission paths from oldest to newest—submarine telegraph cables, wireless communication, submarine coaxial cables, satellite communication, and submarine optical cables—you can see that wired and wireless technologies have taken turns as the leading role, much like the rise and fall of the Genji and Heike clans.