Shimane Prefecture is situated on the Sea of Japan side of the Chūgoku region. Because of its mountainous landscape, rice farming is done mostly in the Izumo plain where the city of Izumo is located. Another major landform is the Shimane peninsula. The peninsula is located across the Sea of Japan from Izumo to Sakaiminato, which is located in Tottori prefecture. Also, the peninsula created two sea water lakes, Lake Shinji and Nakaumi. The island of Daikon is located in Nakaumi. Off the main island of Honshū, the island of Oki is in Shimane prefecture as well. The island itself is in the Daisen-Oki National Park. Shimane also claims the use of Liancourt Rocks, over which they are in dispute with South Korea.