Shimane Prefecture

Shimane Prefecture (島根県, Shimane-ken) sits in the Chūgoku region on the island of Honshu, Japan. With a population of 665,205 as of February 1, 2021, it is the country’s second-least populous prefecture. Its area covers 6,708.26 square kilometers. To the southwest lies Yamaguchi Prefecture, Hiroshima Prefecture borders it on the south, and Tottori Prefecture lies to the east. The capital and largest city is Matsue, followed by Izumo, Hamada, and Masuda. The Lake Shinji-Nakaumi metropolitan area, centered on Matsue, holds roughly 600,000 people, making it Japan’s third-largest urban zone along the Sea of Japan coast, behind only Niigata and Greater Kanazawa. Shimane is known for Izumo-taisha, one of the oldest Shinto shrines, and the Tokugawa-era Matsue Castle.

Shimane’s history begins in Japanese mythology. The god Ōkuninushi was said to live in the old province of Izumo, now part of Shimane, and Izumo Shrine in the city of Izumo honors him. For centuries, the area was split into three provinces: Iwami, Izumo, and Oki. This arrangement lasted until the han system was abolished in 1871. During the Nara period, the poet Kakinomoto no Hitomaro wrote about Shimane’s nature while serving as royal governor. In the Kamakura period (1185–1333), the shogunate exiled emperors Go-Toba and Godaigo to Oki. Emperor Go-Daigo later escaped from Oki and gathered supporters, successfully rallying against the shogunate.

During the Muromachi period (1336–1573), the Kyōgoku clan controlled Izumo and Oki. After the Ōnin War, the Amago clan grew powerful from Gassantoda Castle, while the Masuda clan dominated Iwami Province. The Iwami Ginzan Silver Mine lay between their territories, sparking many battles over the silver. In 1566, Mōri Motonari conquered Izumo, Iwami, and Oki. After the Battle of Sekigahara in 1600, Horio Yoshiharu took over Izumo and Oki, as Mōri lost. Yoshiharu moved to build Matsue Castle instead of Gassan-Toda, and it was completed shortly after his death. In 1638, Matsudaira Naomasa, grandson of Tokugawa Ieyasu, became ruler when the Horio clan had no heir; his family governed until the han system ended. Iwami was split into three parts: the mining district under direct shogunate control, the Hamada clan region, and the Tsuwano clan region. The Iwami Ginzan, now a UNESCO World Heritage Site, was one of Japan’s largest silver mines by the early 1600s. In the Meiji Restoration, the Hamada clan sided with the shogunate, and its castle was burned down. The Tsuwano clan, then ruled by the Matsudaira, supported the emperor.

In 1871, the abolition of the han system placed the old Shimane and Hamada Provinces into the current Shimane Prefecture. Later that year, Oki became part of Tottori. In 1876, Hamada Prefecture merged into Shimane, and Tottori Prefecture was added as well. However, in 1881, the current Tottori Prefecture was separated, forming today’s borders.

Shimane lies on the Sea of Japan side of the Chūgoku region. Its mountainous terrain limits rice farming mostly to the Izumo plain, near the city of Izumo. Another major feature is the Shimane Peninsula, which stretches from Izumo to Sakaiminato in Tottori Prefecture. This peninsula creates two brackish lakes: Lake Shinji and Nakaumi, with Daikon Island located in Nakaumi. Off the main island of Honshu, the Oki Islands belong to Shimane and are part of the Daisen-Oki National Park. Shimane also claims the Liancourt Rocks (Takeshima), a territory disputed with South Korea. As of April 1, 2012, 6% of the prefecture’s land was designated as Natural Parks, including Daisen-Oki National Park, Hiba-Dōgo-Taishaku and Nishi-Chūgoku Sanchi Quasi-National Parks, and eleven Prefectural Natural Parks. Most major cities sit along the coast or a river.

Eight cities make up Shimane, with Matsue the largest and Gōtsu the smallest. Cities like Masuda, Unnan, Yasugi, and Gōtsu saw slight population increases due to mergers in the early 2000s. Towns and villages, though greatly reduced in number through mergers, still hold about one-third of the prefecture’s population.

Shimane has a subtropical climate. Winters are cloudy with light snow, and summers are humid. The average annual temperature is 14.6°C (58.3°F). The rainy season, from June to mid-July, brings rain nearly every day. August is the warmest month, averaging 26.3°C (79.3°F). Average annual precipitation is 1,799 millimeters (70.8 inches), higher than Tokyo’s 1,467 mm (57.8 in) and Obihiro’s 920 mm (36.2 in).

Three airports serve Shimane. Izumo Airport, in the city of Izumo, is the largest by passenger traffic and offers regular flights.