is a prefecture of Japan located in the Chūgoku region on the main Honshu island. The capital is Matsue. It is the second least populous prefecture in Japan, after its eastern neighbor Tottori. The prefecture has an area elongated from east to west facing the Chūgoku Mountain Range on the south side and to the Sea of Japan on the north side. It is divided into the Izumo Region in the East, the Iwami Region in the West and the Oki Region, a small group of islands off the northern coast. Most of the cities are near the shoreline of the Sea of Japan. Izumo Taisha in Izumo City is one of the oldest Shinto shrines in Japan.
The history of Shimane starts with Japanese mythology. The Shinto god Ōkuninushi was believed to live in Izumo, an old province in Shimane. Izumo Shrine, which is in the city of Izumo, honors the god. At that time, the current Shimane prefecture was divided into three parts: Iwami, Izumo, and Oki. That lasted until the abolition of the han system took place in 1871. During the Nara period, Kakinomoto no Hitomaro read a poem on Shimane's nature when he was sent as the Royal governor.
Later on in the Kamakura period, Kamakura Shogunate forced emperors Gotoba and Emperor Godaigo into exile to Oki. Emperor Godaigo later escaped away from Oki and began rallying supporters against the shogunate, which succeeded.
During the Muromachi period, Izumo and Oki were controlled by the Kyogoku clan. However, after the Ōnin War, the Amago clan expanded power based in Gassantoda Castle and the Masuda clan dominated Iwami province. The Iwami Ginzan Silver Mine was located between Amago territory and Masuda territory, so there were many battles between these clans for the silver. However, in 1566 Mori Motonari conquered Izumo, Iwami, and Oki. After over 30 years of Mori control, in 1600 Horio Yoshiharu entered Izumo and Oki as the result of Battle of Sekigahara, which Mori lost. Following the change, Horio Yoshiharu decided to move to build Matsue Castle instead of Gassan-Toda, and soon after Yoshiharu's death the castle was completed. Later in 1638, the grandson of Tokugawa Ieyasu, Matsudaira Naomasa became the ruler because the Horio clan had no heir, and his family ruled until the abolition of the han system.
The Iwami area was split into three regions: the mining district, under the direct control of the Shogunate, the Hamada clan region, and the Tsuwano clan region. The Iwami Ginzan, now a UNESCO World Heritage Site produced silver and was one of the nation's largest silver mine by the early 17th century. The Hamada clan was on the shogunate's side in the Meiji Restoration, and the castle was burned down. The Tsuwano clan, despite the being ruled by the Matsudaira, was on the emperor's side in the restoration.
In 1871, the abolition of the han system placed the old Shimane and Hamada Provinces in the current area of Shimane Prefecture. Later that year, Oki became part of Tottori. In 1876, Hamada Prefecture was merged into the Shimane Prefecture. Also, Tottori Prefecture was added in the same year. However, five years later, in 1881, the current portion of Tottori Prefecture was separated and the current border was formed.