Aonodōmon

Along the flowing Yamunikugawa River in Nakatsu City, Oita Prefecture, steep cliffs rise sharply beside a clear stretch of water. Carved directly into the rocky face is a roughly hewn tunnel known as Aonodōmon. Its walls bear the uneven scars left by hand tools, a result of thirty years of persistent labor undertaken during the Edo period by a monk who sought to create a safer passage through the perilous cliffs.

The tunnel’s interior reveals rough, unpolished surfaces marked with countless chisel cuts. Openings were carved to allow light and remove debris, and the uneven ceiling and walls reflect the painstaking manual work performed without modern machinery or explosives. Outside the tunnel, the river and surrounding greenery can be seen through gaps in the rock.

Walking through Aonodōmon today, visitors move along a path shaped by historical effort, accompanied by the sounds of the river and wind. The surrounding landscape changes with the seasons, framing the enduring marks of the tunnel’s excavation and preserving the record of this challenging natural passage.