Kōchi Prefecture

Kōchi Prefecture is a Japanese administrative region on the island of Shikoku. Its population stood at 669,516 as of April 1, 2023, and it covers an area of 7,103 square kilometers. It shares borders with Ehime Prefecture to the northwest and Tokushima Prefecture to the northeast. The capital and largest city is Kōchi; other major cities include Nankoku, Shimanto, and Kōnan. The prefecture sits on Japan’s Pacific coast, wrapping around a large bay in southern Shikoku, with the island’s southernmost point at Cape Ashizuri in Tosashimizu. Notable landmarks include Kōchi Castle—often called the most intact original castle in Japan—and the Shimanto River, one of the country’s few rivers without a dam.

In antiquity, the earliest recorded governments in the area were Hata (in the west) and Tosa (in the center). The Kujiki suggests Hata was established first, implying it had more influence and contact with the Yamato court. Written records from that time are scarce, but it is thought the first governors of Hata and Tosa came from the Kamo clan, based in what is now Osaka. The Nihon Shoki contains the first official report from the Kōchi region, describing damage from the 684 Hakuhō earthquake. This indicates that by 684 at the latest, Tosa Province—the predecessor to modern Kōchi Prefecture—had been formed. The first report from a named official came in 743, written by Hiketa no Mushiro. Up to the Genpei War, 106 governors were appointed to Tosa. Like many provinces, Tosa eventually received absentee governors, gained additional rights, and accumulated wealth. Its distance from the capital made it a common destination for exiled prisoners.

During the Kamakura period, which began at the end of the 12th century, Tosa allied with the victorious Minamoto clan in the Genpei War and quickly fell under shogunate influence. Kajiwara Tomokage became the first military governor, and later the Hōjō clan took over that role. After the Kamakura Shogunate fell, Ashikaga Takauji was defeated in battle and fled to Kyushu, and Shikoku Island came under the control of the Hosokawa clan. In the Sengoku period, the Chōsokabe clan ruled Tosa, and during the Edo period, the Yamauchi clan held power. The city of Kōchi is also the birthplace of Sakamoto Ryōma, a key figure in the Meiji Restoration.

Geographically, Kōchi Prefecture covers the southwestern part of Shikoku, facing the Pacific Ocean. It is the largest of Shikoku’s four prefectures but the least populous. Most of the region is mountainous, with coastal plains only around Kōchi and Nakamura. Inamura-yama in Tosa-cho is the highest peak, at 1,506 meters. Kōchi has the highest percentage of mountainous land of any Japanese prefecture—89%, compared to the national average of 66%. Because it lies in the Shimanto Group geological area, the prefecture has many sedimentary rocks and is prone to landslides. Major rivers include the Shimanto River in the west, the Niyodo River flowing from Mount Ishizuchi into Tosa Bay, and the Yoshino River, which flows into Tokushima Prefecture. Historically, water shortages have not been a problem, but river management has been a persistent challenge. In the early Edo period, samurai Nonaka Kenzan oversaw large-scale improvements to the Tosa Domain’s major rivers. Modern Kōchi is known for effective river management and minimal water damage despite heavy rainfall. The Kuroshio Current flows along the coast, keeping the water warm even in winter and contributing to frequent typhoons. Kōchi experiences the second-highest number of typhoons of any Japanese prefecture, after Kagoshima. The 1934 Muroto Typhoon was particularly severe, recording the lowest central pressure of any typhoon to make landfall in Japan—911.6 hPa—when it hit Muroto Cape. The Ashizuri and Muroto capes are known for strong winds. As of April 1, 2012, 7% of the prefecture’s land was designated as Natural Parks, including Ashizuri-Uwakai National Park; Ishizuchi, Muroto-Anan Kaigan, and Tsurugisan Quasi-National Parks; and eighteen Prefectural Natural Parks.

The prefecture contains eleven cities: Kōchi, Nankoku, Shimanto, Kōnan, and others. It also has numerous towns and villages organized into districts, with some mergers having occurred over time.

Tourist attractions include Aki Castle and the Doi Kachū samurai residence district; the Anpanman Museum; Godaisan; Katsurahama and its aquarium; Kōchi Castle (one of only twelve original castles left in Japan); the Kōchi Prefectural Museum of History, located on Okō Castle; the Muroto Schoolhouse Aquarium; Okō Castle, the ruined stronghold of the Chōsokabe clan; Ryūga Cave, one of Japan’s top three caves; the Sakamoto Ryōma Memorial Museum; and the Shimanto River, the only undammed river in Japan.

Several movies have been set in Kōchi. These include the 1993 Studio Ghibli film *Ocean Waves* (*Umi ga Kikoeru*); the 2009 film *The Harimaya Bridge*, starring Danny Glover; the 2013 film *Hospitality Department* (*Kencho Omotenashi Ka*), which features views of the prefecture; and the 2021 film *Bel*.