Ryogoku (両国) is the home of sumo in Tokyo. The Ryogoku Kokugikan where three of the six annual sumo honbasho tournaments take place (in January, May, and September) is the fourth incarnation after the first sumo hall was built in Ryogoku in 1909, and the backstreets between Ryogoku and Kiyosumi Shirakawa is home to many of the sumo stables where the wrestlers train. Naturally for a neighbourhood with some many sumo wrestlers, it’s the best place to go to in Tokyo to experience chanko nabe—the favoured dish of the wrestlers. You can read more about the history of the sport here.
Ryogoku is not just all about sumo, however. It is also home the Edo-Tokyo Museum, which traces the history of the capital over the past 400 years, as well as Yokoamicho Park which commemorates the victims of the 1923 Great Kanto Earthquake and the air raids of World War II.