Beginning in 1896, the Sōtokufu (the Government-General of Taiwan) introduced the licensed prostitution system (kōshō seido) from mainland Japan to various districts in Taiwan. However, this gradually created regulatory gaps between local districts, often resulting in conflicts and disputes over the validity of prostitute indentures. In an effort to resolve these issues, the Sōtokufu standardized the system in 1906. In 1910, mandatory notarization of prostitute indentures by Japanese Court Officials became a prerequisite for their legal validity. This requirement also served as a tool to effectively safeguard the ＂human rights of prostitutes.＂ Despite its abrogation in 1918, the discourse behind the introduction as well as abrogation of mandatory notarization is worth examining, not only because of the apparent contradiction between the inhumane nature of Japanese prostitute per se, but also due to its uniqueness in the context of modern Japanese history. Ever since the Maria Luz Incident (1872), in order to avoid criticism from the West, explicit references to prostitutes in official documents, including indentures between prostitutes and panderers, were rare. In contrast, more than 1,000 prostitute indentures notarized in the 1910s were compiled and stored in the Taiwan Colonial Court Record Archives, detailing the working terms and conditions within the sex market in early colonial Taiwan. This article first traces the 1910 regulation on the notarization of prostitute indentures and its abolition in 1918 to understand the regulatory measures and objectives of the Sōtokufu as well as the socio-economic conditions that influenced these legal processes. Through analysis of 356 prostitute indentures from Taihoku District in the Taiwan Colonial Court Records Archive, this article also attempts to map out the underlying demographic landscape of early colonial Taiwan's sex industry, particularly the existence of a community of Japanese prostitutes and their lived experiences. Finally, this article evaluates the gaps between the original intent and the actual effects of the mandatory notarization of the prostitute indentures in Taiwan.