Shibukawa (渋川市, Shibukawa-shi?) is a city located in the extreme northwest of the Kantō Plain, in the center of landlocked Gunma, Japan. Encompassing the juncture of the Tone River and Agatsuma River, it is about 120 km from Tokyo. Due to its location at the geographical center of the nation, Shibukawa is known as the Bellybutton of Japan (日本のおへそ, nihon no oheso).