"Tokyo" is an organization responsible for the Alphabet Project, the research institution on Hinamizawa Syndrome, and ultimately the Great Hinamizawa Disaster (GHD). "Tokyo" members consist of very powerful figures such as governmental and political people. Within this organization, there are the three main members who investigate directly in Hinamizawa Village: Irie Kyōsuke, Takano Miyo, and Tomitake Jirō.
A woman named Nomura appears to be the main character who works behind the scenes in "Tokyo" to support Takano's research and help plan for the GHD; much of her background and motives remain a mystery and are unsolved even after the end of the Higurashi series. For example, even though in Matsuribayashi-hen Nomura tells Takano she will aid her research of the Hinamizawa Syndrome, there is evidence that Nomura is only using Takano as a tool for her own purposes. After she informed Takano, who is backed by Koizumi and the Alphabet Project, that she planned a new facility for Takano's research, she directs another call to someone else in "Tokyo" saying that she already planned to use Document #34 even before Takano received the notice of the Irie Clinic being shut down early, and that once the disaster happens, "The Alphabet will be questioned, and the Koizumi faction will lose their power". Even Nomura's true identity is unclear, as Nomura may only be a name she uses when speaking with Takano and the Yamainu. When directing other calls, she used the various names such as "Watanabe", "Maizawa", and "Takagi".