Rakanji Bridge, Stone arch road bridge in Nakatsu, Japan.

Rakanji Bridge is an 89 m long stone bridge with three arches over the Yamakuni River in Nakatsu, Oita Prefecture. Its arches are flat and shallow: each span measures 26.25 m while the rise is only 4.6 m, giving the 4.5 m wide roadway a nearly horizontal line. It was completed in 1920 by the mason Iwabuchi Manekichi.

The structure was built in 1920 during a time when Japan rapidly expanded its modern infrastructure. Builders relied on proven local methods and materials that had worked for generations.

The bridge stands about 500 m upstream of Aonodōmon and, with Makyō Bridge upstream and Yabakei Bridge downstream, forms the Yabakei Three Bridges. Until the Yabakei Railway line closed in 1975, Rakanji Station stood near it, on the approach to Rakanji temple, head temple of Japan's Rakanji temples.

The bridge can be crossed on foot or by vehicle, with clear markings for both directions. It sits close enough to the city center to be easily reached, and offers good views over the river.

The bridge's arches are unusually flat: each 26.25 m span rises only 4.6 m, giving the 89 m crossing a nearly horizontal profile. This shallow shape made load transfer difficult, and the bridge is said to have collapsed during construction before its completion in 1920.