In 1924, the Treaty of Equality and Mutual Understanding between the Republic of Japan and the South Pacific Islands was signed by Suzuki Bunji, the then-Prime Minister of Japan, and Isabelo de los Reyes, the representative of Philippine National Assembly. The treaty established the islands as a dependency and an associated state of the Republic of Japan with political and cultural autonomy.
In 1917, the Japanese colonial government divided the former Spanish East Indies into three provinces: Luzon (呂宋道 Ruson-dō), the Visayas (比佐夜道 Bisaya-dō), and Mindanao (民太那部道 Mindanō-dō). Manila, former capital of the Spanish East Indies, continued to serve as the seat for the Japanese colonial government.
Until 1923, the highest authority in the islands resided on the Office of the Governor-General, headed by a Governor-General. The Governor-General functioned as chief of executive of the colonial government and had supreme executive, legislative, and judicial powers. The South Pacific colonial government was composed of two bureaus: Home Affairs and Military Affairs. The Home Affairs Bureau was divided again into six offices: Internal Affairs, Agriculture, Finance, Education, Judicial and Communications.The Governor-General had sweeping plenipotentiary powers and some legislative powers, but required to consult a 15-membered Central Advisory Council on major issues. The Council acted as an advisory board for the Governor-General. During its early years, the fifteen members of the Council were personally appointed by the Governor-General from prominent political leaders of native South Pacific population.
When the Republic of Japan took over the control of the islands in 1923, this Office of the Governor-General was replaced by the Office of the High Commissioner, headed by a High Commissioner following the Commonwealth Law of 1919. The bureaus of the colonial government were abolished and replaced by new governmental departments that each headed by a secretary (referred as "chief"). This departments included Civil Administration, Agriculture, Finance, Education, Trade, Defense, Civil Law, Islamic Law, Communications and Public Works.
The State Council was established in place of the Central Advisory Council. The State Council, while retained the advisory role of its preceding institution, was gained some significant legislative powers. Its membership was enlarged from 15 to 100. 70 members were elected every four years by the Provincial Councils (30 from Luzon, 25 from the Visayas and 15 from Mindanao) while remaining 30 members were appointed personally by the High Commissioner.
The Treaty between the Republic of Japan and the South Pacific Islands in 1924 provided a dual form of government for the islands. Some areas of government, included the departments of Civil Administration, Agriculture, Education, Communications and Public Works, were answerable to the State Council. On other hand, the rest of governmental departments, included Defense, Finance, Trade, Civil Law and Islamic Law remained under the Office of High Commissioner. The departments that answerable to the State Council were collectively (and informally) called as the General Government of the Philippines (Pamahalaang Pangkalahatan ng Kapilipinuhan). The Chief of Civil Administration served as de facto head of the General Government and informally referred as the Premier (Pangasiwa).