龍頭橋, Footbridge in Kitsuki, Japan

Ryuto Bridge (Ryuzu-bashi) is a stone submersible bridge over the Yasaka River in Kitsuki, Oita Prefecture. Completed in 1912, it has 11 spans, a length of 61.5 m and a width of 3.0 m; its low stone piers let water flow over the deck during floods.

Completed in 1912 (Meiji 45), Ryūzu Bridge is the oldest surviving stone submersible bridge in Japan. It was built across the upper Yasaka River as an 11-span structure 61.5 m long and 3.0 m wide. It gained this status after the 1876 Nagase Bridge, then considered the oldest, was washed away by Typhoon 21 on 29 September 2004.

The bridge's name, Ryūzu-bashi ("dragon head bridge"), is the detail to look for locally. It is a low stone sinking bridge over the upper Yasaka River, built to let high water pass over its deck; the 11 spans and 3.0 m width shape how people cross it today.

Access is available 24 hours daily, and nearby public transportation stops make it easy to reach the location. The terrain offers level paths that are straightforward for most visitors to navigate.

The bridge is a submersible crossing: its low deck is designed to be covered by the Yasaka River in flood and reappear afterwards. It has 11 stone spans over 61.5 m, and in 2007 the Japan Society of Civil Engineers listed it as a selected civil engineering heritage site.