Sekizaki Lighthouse

Sekizaki Lighthouse: Oita Prefecture's Oldest Beacon on the Hoyo Strait

Standing at the very tip of the Saganoseki Peninsula in Oita City, Sekizaki Lighthouse has been guiding vessels through one of Japan's most treacherous waterways since 1901. This iron-built lighthouse — one of only four all-iron lighthouses still in active service across the nation — was designated a Registered Tangible Cultural Property in June 2022, honoring more than 120 years of maritime heritage. Facing the Sadamisaki Lighthouse on Shikoku across the narrow Hoyo Strait, Sekizaki Lighthouse marks the gateway between the Seto Inland Sea and the Pacific Ocean.

Historical Background

Sekizaki Lighthouse was first lit on July 20, 1901 (Meiji 34), making it the oldest lighthouse in Oita Prefecture. At the time of its construction, there were no roads leading to the remote cliff-top site; all building materials had to be transported by boat and hauled up steep cliffs. The lighthouse keepers and their families lived in quarters on the lighthouse grounds, essentially isolated from the outside world — a situation that persisted until the 1950s, when road access was finally established. Children of the lighthouse keepers walked five kilometers along rugged mountain paths to reach school each day.

When first lit, the lighthouse used a French-made Third Order Fresnel lens with a kerosene oil lamp as its light source. The soot from the oil lamps required constant cleaning, a task that continued until the lighthouse was electrified in 1926 (Taisho 15). In 1918, the original Fresnel lens was transferred to the newly completed Sadamisaki Lighthouse on the Shikoku side. It was replaced by a British-made Fourth Order Fresnel lens, which faithfully served for approximately ninety years until being retired in favor of LED technology in February 2009. That historic British lens is now on display at the nearby JX Metals Sekizaki Mirai Kaiseikan observatory.

The lighthouse was automated and unmanned in April 1970. Notably, the lighthouse supply vessel "Soya" — which later gained fame as the ship used for Japan's Antarctic expeditions — once called at Sekizaki during its supply runs. The lighthouse underwent renovation and renewal in 2024 (Reiwa 6), restoring it to its original splendor.

Why It Was Designated a Cultural Property

In June 2022, Sekizaki Lighthouse was registered as a national Registered Tangible Cultural Property (building). The designation recognizes several key aspects of its significance. The lighthouse is one of only four iron-built lighthouses in Japan that remain in active operation, with its entire structure — both the cylindrical light tower and the fan-shaped annex building — constructed from 6-millimeter-thick iron plates shaped into curves and fastened with rivets. This Meiji-era ironwork construction technique is extremely rare among surviving Japanese lighthouses. The structure consists of a three-story iron tower 11 meters tall with a diameter of 3 meters, topped by a balcony and a domed lantern room. The total building area is 39 square meters. As the oldest lighthouse in Oita Prefecture, it represents a valuable piece of Japan's maritime engineering heritage from the early twentieth century.

Highlights and Things to See

The lighthouse itself is a striking sight — a white cylindrical iron tower rising above the rugged coastline at the very end of the Saganoseki Peninsula. On clear days, visitors can see the Sadamisaki Peninsula of Shikoku across the Hoyo Strait, just 14 kilometers away. The view of the churning waters of the strait — known as the Hayasui Strait — is mesmerizing, with powerful tidal currents and whirlpools visible below.

The grounds around the lighthouse are particularly beautiful in winter and spring. Approximately 800 wild camellia trees grow naturally in the surrounding forest, blooming with red flowers from winter into early spring. The area is also within the Nippo Kaigan Quasi-National Park and is known as a cherry blossom viewing spot.

While the interior of the lighthouse is not normally accessible to the public, it is opened for special viewing events around Lighthouse Day (November 1) each year, weather permitting. The foundations and remnants of the former lighthouse keepers' quarters can still be seen on the grounds, offering a tangible connection to the lives of those who once maintained this remote beacon.

Nearby Attractions

The lighthouse is located within walking distance of the JX Metals Sekizaki Mirai Kaiseikan, an observatory and planetarium facility perched on the hilltop above. Reopened in July 2023 after a major renovation, the facility houses Oita Prefecture's largest astronomical telescope (83 cm aperture), a digital planetarium, and a panoramic observation deck offering 300-degree ocean views. The former Fresnel lens from Sekizaki Lighthouse is exhibited here. A scenic walking trail connects the observatory to the lighthouse.

The Saganoseki district is famous as the fishing ground for "Seki-aji" (horse mackerel) and "Seki-saba" (mackerel), two of Oita's most prized seafood brands. Several local restaurants in the Saganoseki port area serve these delicacies fresh. The nearby white-stone beach of Koshiro-hama within the Nippo Kaigan Quasi-National Park is popular for swimming and camping in summer. Visitors can also explore the historic Saganoseki port town, which has a long history tied to the fishing and smelting industries.