Mizunokojima Lighthouse

An active beacon guides ships through the Bungo Channel from Mizunokojima, a small rocky island about 25 km east‑northeast of Saiki in Ōita Prefecture.

The stone tower is cylindrical, built of stone, and features a balcony and lantern. Its exterior is marked with alternating black and white horizontal bands, while the lantern is painted white. The tower rises 39.25 m, and the light’s focal plane is 56.3 m above sea level. At 39.25 m it ranks among the tallest Japanese lighthouses. The white flash repeats every ten seconds (Fl W 10 s) and can be seen for 20 nmi, with an intensity of 1,200,000 cd.

The lighthouse began operation on 20 March 1904 after a four‑year construction period marked by the difficulty of its remote site. Service was suspended on 4 May 1945 during World War II, but acetylene lamps restored illumination on 17 May 1946; the main light was repaired on 15 November 1950. The station was manned until automation in 1986. Solar and wave‑power generators were added in 2002, and the tower has withstood severe typhoons that once drove waves over its roof and damaged its pier.

The light remains operational under the Japan Coast Guard, which maintains the tower and the nearby two‑story keeper’s house. The beacon continues to serve maritime traffic through the Bungo Channel.

Light and tower

Its light characteristic is Fl W 10s. The Admiralty list of lights numbers it M4912.