Japan Information Highway (JIH)

Overview

The Japan Information Highway (JIH) is a domestic submarine cable system operating entirely within Japan. Spanning approximately 5,150 kilometres, it connects multiple landing points along the Japanese coastline, forming a ring-shaped network that links the country's main island of Honshu with more outlying regions including Hokkaido and the Ryukyu Islands. The cable serves an intra-Japan corridor, providing connectivity between geographically dispersed coastal cities and prefectures.

Route and Landings

All nine landing points are located in Japan. On Honshu, the cable lands at Akita, Chikura, Ibaraki, Ninomiya, Sendai, and Shima. The landing at Miyazaki is situated on the island of Kyushu. Naha, located in Okinawa Prefecture, represents the southernmost landing point in the Ryukyu Islands chain. Ishikari is located on the northernmost main island of Hokkaido. Together, these nine stations distribute the cable across a broad arc of the Japanese coastline.

Ownership and Operators

JIH is owned and operated by KDDI Corporation. KDDI is one of Japan's principal telecommunications carriers, providing a wide range of domestic and international communications services. As the sole owner of this system, KDDI manages the cable's operation and maintenance without a consortium structure.

Technical Profile

The JIH cable has a total length of 5,150 kilometres, making it a substantial domestic system given that all landing points are contained within Japanese territory.

Status and Timeline

The Japan Information Highway entered service in 1999. The system has been in operation for over two decades, providing continuous domestic connectivity across its nine landing stations.

Regional Context

Japan's submarine cable environment includes numerous long-haul international systems connecting the country to the broader Asia-Pacific region and beyond. Cables such as APCN-2 (19,000 km, RFS 2001), EAC-C2C (36,500 km, RFS 2002), the Trans-Pacific Express Cable System (17,968 km, RFS 2008), the Australia-Japan Cable (12,700 km, RFS 2001), the New Cross Pacific Cable System (13,618 km, RFS 2018), and JUPITER (14,557 km, RFS 2020) all land in Japan and serve international routes. JIH is distinct from these systems in that it operates entirely within Japan, focusing on domestic interconnection rather than transoceanic reach.

Strategic Role

By linking nine coastal locations spanning Hokkaido in the north, multiple points along Honshu, Kyushu, and the Okinawa islands in the south, JIH enables domestic data exchange across a geographically elongated and seismically complex archipelago. The use of submarine cable infrastructure for intra-Japan connectivity reflects the practical challenges of building terrestrial links across an island nation with difficult terrain, and allows KDDI to maintain a resilient domestic network path independent of land-based routes.