When we look at the city of Tokyo from a historical perspective, the “local resources of the waterfront since the Edo period” centering on the Kanda River, the Nihonbashi River, and the outer moat have immeasurable value. In the Tenmasen Project, a miniature Tenmasen boat (about 25 cm long), modeled after Japanese traditional wooden boats, will be floated on the Kanda River (between Hijiribashi and Manseibashi), and time trials will be held, following the flow of the river. For every 1,000 yen donated, participants will register one miniature Tenmasen boat, and on the day of the event, they will be able to watch the miniature Tenma boats all flowing together from the river’s upstream via webcast. Part of the donation proceeds will be used toward river clean-up, promotion of river culture. This is an art project that aims to change people’s awareness of the river through the event and donations.