The Nihonbashi River (日本橋川, Nihonbashi-gawa) is a river which flows through central Tokyo, Japan. It is a distributary river of the Kanda River and flows into the Sumida River near the Eitai Bridge.
The river is 4.8 km (3.0 mi) in length and passes through Chiyoda and Chuo wards. The river was created by a re-channeling of the former Hira River in the 15th century at the direction of Ōta Dōkan to form a part of the external fortifications and water management plan for Edo Castle.
Kudanminami (九段南) is a district of Chiyoda, Tokyo, Japan, consisting of 1-chōme to 4-chōme. As of March 1, 2007, its population is 2,431.
Kudanminami is located on the northwestern part of the Chiyoda ward. The Nihonbashi River and Yasukuni-dōri Ave form its eastern and northern boundaries, respectively. It borders Kanda-Jinbōchō to the east, Gobanchō to the west, Sanbanchō, Hitotsubashi and Yonbanchō to the south, and Kudankita to the north. In addition, it borders Kitanomaru Kōen between its 1-chōme and 2-chōme. The zone is a prestigious business and residential zone.
Nihonbashi (日本橋, Nihonbashi; Japanese pronunciation: [ɲi.hon.ba.ɕi], also romanized as Nihombashi Japanese pronunciation: [ɲi.hom.ba.ɕi], Nippombashi Japanese pronunciation: [ɲip.po(ꜜ)m.ba.ɕi], or Nipponbashi Japanese pronunciation: [ɲip.po(ꜜ)n.ba.ɕi]) is a business district of Chūō, Tokyo, Japan, which sprung up around the bridge of the same name that has linked two sides of the Nihonbashi River at this site since the 17th century. The first wooden bridge was completed in 1603. The current bridge, designed by Tsumaki Yorinaka and constructed of stone on a steel frame, dates from 1911. The district covers a large area to the north and east of the bridge, reaching Akihabara to the north and the Sumida River to the east. Ōtemachi and Yaesu are to the west and Kyobashi to the south.
Nihonbashi, together with Kyobashi and Kanda, is the core of Shitamachi, the original downtown center of Edo-Tokyo, before the rise of newer secondary centers such as Shinjuku and Shibuya.