A ku (区), translated as ward, is a district in a large Japanese city.  Wards are used to subdivide each city designated by government ordinance, as well as Tokyo (where the "23 special wards" have a quasi-municipal status).

Outside of Tokyo, wards are local entities directly controlled by the municipal government. They handle administrative functions such as koseki registration, health insurance, and property taxation. Many wards have affiliated residents' organizations for a number of tasks, although these do not have any legal authority per se.

List of wards

• Abeno-ku, Osaka
• Adachi-ku, Tokyo
• Aki-ku, Hiroshima
• Aoba-ku, Sendai
• Aoba-ku, Yokohama
• Arakawa-ku, Tokyo
• Asahi-ku, Osaka
• Asahi-ku, Yokohama
• Asakita-ku, Hiroshima
• Asaminami-ku, Hiroshima
• Asao-ku, Kawasaki
• Atsubetsu-ku, Sapporo
• Atsuta-ku, Nagoya

• Bunkyo-ku, Tokyo

• Chikusa-ku, Nagoya
• Chiyoda-ku, Tokyo
• Chuo-ku, Chiba
• Chuo-ku, Fukuoka
• Chuo-ku, Kobe
• Chuo-ku, Osaka
• Chuo-ku, Saitama
• Chuo-ku, Sapporo
• Chuo-ku, Tokyo

• Edogawa-ku, Tokyo

• Fukushima-ku, Osaka
• Fushimi-ku, Kyoto

• Hakata-ku, Fukuoka
• Hanamigawa-ku, Chiba
• Higashi-ku, Fukuoka
• Higashi-ku, Hiroshima
• Higashi-ku, Nagoya
• Higashi-ku, Sapporo
• Higashinada-ku, Kobe
• Higashinari-ku, Osaka
• Higashisumiyoshi-ku, Osaka
• Higashiyama-ku, Kyoto
• Higashiyodogawa-ku, Osaka
• Hirano-ku, Osaka
• Hodogaya-ku, Yokohama
• Hyogo-ku, Kobe

• Ikuno-ku, Osaka
• Inage-ku, Chiba
• Isogo-ku, Yokohama
• Itabashi-ku, Tokyo
• Iwatsuki-ku, Saitama
• Izumi-ku, Sendai
• Izumi-ku, Yokohama

• Jonan-ku, Fukuoka
• Joto-ku, Osaka

• Kamigyo-ku, Kyoto
• Kanagawa-ku, Yokohama
• Kanazawa-ku, Yokohama
• Katsushika-ku, Tokyo
• Kawasaki-ku, Kawasaki
• Kita-ku, Kobe
• Kita-ku, Kyoto
• Kita-ku, Nagoya
• Kita-ku, Osaka
• Kita-ku, Saitama
• Kita-ku, Sapporo
• Kita-ku, Tokyo
• Kiyota-ku, Sapporo
• Kohoku-ku, Yokohama
• Kokurakita-ku, Kitakyushu
• Kokuraminami-ku, Kitakyushu
• Konan-ku, Yokohama
• Konohana-ku, Osaka
• Koto-ku, Tokyo

• Meguro-ku, Tokyo
• Meito-ku, Nagoya
• Midori-ku, Chiba
• Midori-ku, Nagoya
• Midori-ku, Saitama
• Mihama-ku, Chiba
• Minami-ku, Fukuoka
• Minami-ku, Hiroshima
• Minami-ku, Kyoto
• Minami-ku, Nagoya
• Minami-ku, Saitama
• Minami-ku, Sapporo
• Minami-ku, Yokohama
• Minato-ku, Nagoya
• Minato-ku, Osaka
• Minato-ku, Tokyo
• Minuma-ku, Saitama
• Miyagino-ku, Sendai
• Mizuho-ku, Nagoya
• Moji-ku, Kitakyushu
• Moriyama-ku, Nagoya
• Miyakojima-ku, Osaka
• Miyamae-ku, Kawasaki

• Nada-ku, Kobe
• Nagata-ku, Kobe
• Naka-ku, Hiroshima
• Naka-ku, Nagoya
• Naka-ku, Yokohama
• Nakagawa-ku, Nagoya
• Nakagyo-ku, Kyoto
• Nakahara-ku, Kawasaki
• Nakamura-ku, Nagoya
• Nakano-ku, Tokyo
• Naniwa-ku, Osaka
• Nerima-ku, Tokyo
• Nishi-ku, Kobe
• Nishi-ku, Hiroshima
• Nishi-ku, Osaka
• Nishi-ku, Saitama
• Nishi-ku, Sapporo
• Nishi-ku, Yokohama
• Nishikyo-ku, Kyoto
• Nishinari-ku, Osaka
• Nishiyodogawa-ku, Osaka

• Omiya-ku, Saitama
• Ota-ku, Tokyo

• Saeki-ku, Hiroshima
• Saiwai-ku, Kawasaki
• Sakae-ku, Yokohama
• Sakura-ku, Saitama
• Sakyo-ku, Kyoto
• Sawara-ku, Fukuoka
• Setagaya-ku, Tokyo
• Seya-ku, Yokohama
• Shibuya-ku, Tokyo
• Shimogyo-ku, Kyoto
• Shinagawa-ku, Tokyo
• Shinjuku-ku, Tokyo
• Shiroishi-ku, Sapporo
• Showa-ku, Nagoya
• Suginami-ku, Tokyo
• Suma-ku, Kobe
• Sumida-ku, Tokyo
• Suminoe-ku, Osaka
• Sumiyoshi-ku, Osaka

• Taihaku-ku, Sendai
• Taisho-ku, Osaka
• Taito-ku, Tokyo
• Takatsu-ku, Kawasaki
• Tama-ku, Kawasaki
• Tarumi-ku, Kobe
• Teine-ku, Sapporo
• Tennoji-ku, Osaka
• Tenpaku-ku, Nagoya
• Tobata-ku, Kitakyushu
• Toshima-ku, Tokyo
• Totsuka-ku, Yokohama
• Toyohira-ku, Sapporo
• Tsurumi-ku, Osaka
• Tsurumi-ku, Yokohama
• Tsuzuki-ku, Yokohama

• Ukyo-ku, Kyoto
• Urawa-ku, Saitama

• Wakaba-ku, Chiba
• Wakabayashi-ku, Sendai
• Wakamatsu-ku, Kitakyushu

• Yahatahigashi-ku, Kitakyushu
• Yahatanishi-ku, Kitakyushu
• Yamashina-ku, Kyoto
• Yodogawa-ku, Osaka