From the wiki: “Tokyo City’s original 15 wards were first established in 1878, under the Law for Reorganization of Counties, Wards, Towns, and Villages act. In 1888, the Meiji government created the legal framework for the current system of cities (shi) that were granted some basic local autonomy rights – with some similarities to Prussia’s system of local self-government as Meiji government advisor Albert Mosse heavily influenced the organization of local government. The Tokyo city council/assembly (Tōkyō-shikai) was first elected in May 1889.
“The original wards making up Tokyo City from 1878-1932 numbered fifteen: Akasaka, Asakusa, Azabu, Fukagawa, Hongo, Honjo, Kanda, Koishikawa, Kojimachi, Kyobashi, Nihonbashi, Shiba, Shitaya, Ushigome and Yotsuya. On October 1, 1932, large areas from five surrounding suburban and rural districts were absorbed and merged into Tokyo City, organized into 20 new wards, bringing the total to 35. The expanded city became referred to as ‘Greater Tokyo’ (大東京 Dai-Tōkyō). Among the new city wards created in 1932 were Shinagawa, Meguro, Shibuya, Setagaya, Nakano, Mukojima and Yodobashi (later Shinjuku).
“In 1943, the city was abolished and merged with Tokyo Prefecture to form the Tokyo Metropolitan Government. This remained in place until a complete reorganization was undertaken in 1947 during the Occupation, resulting in the present Tokyo-to of 23 wards.”
“Tokyo-to, the capital of the Japanese Empire, is a great diversified metropolitan center and, together with its satellite cities on Tokyo-wan, it is one of the largest and most populous urban areas in the world.
“The 1940 boundaries established in October 1932 included 35 wards (ku) and enclosed an area referred to as ‘Greater Tokyo’. In the area of the 15 wards, which before 1932 formed the inner city, there was a population in 1940 of 2,333,601. The 20 wards added in 1932 formed the outer city. In 1943 Tokyo-shi [city] became, in area and government, identical with Tokyo-fu (urban prefecture), the resulting unit was called Tokyo-to and had a population of 7,354,971. Much of the area absorbed in this latest expansion is essentially rural in character …”
– Civil Affairs Handbook, Japan: Prefectural Studies, Tokyo-to, [U.S.] War Department, September 1945