An immense double-decker bridge, which appears to soar endlessly into the heavens, stands as one of history's most ambitious and costly feats of engineering. The Seto Ohashi Bridge, a colossal structure linking five islands across Japan's Seto Inland Sea, represents a decade of monumental effort and a staggering financial investment.
A Monumental Feat of Engineering and Cost
Construction on this two-tiered coastal landmark began in 1978 and was finally opened to the public over ten years later. The project came with an eye-watering price tag of US$7 billion, equivalent to approximately £5.3 billion. To realise this vision, builders used a mind-boggling 3.646 million cubic metres of concrete and 705,000 tonnes of steel.
The human cost was also significant. Despite extensive safety precautions, 17 workers tragically lost their lives during the bridge's construction. Today, the completed structure holds the record as the world's longest combined railway and road bridge, with a total length of 13.1 kilometres (8.1 miles).
Transforming Travel and Drawing Tourists
The bridge's primary function was to connect Japan's main island of Honshu with Shikoku. It achieved this spectacularly, enabling millions to cross the Seto Inland Sea in just 20 minutes—a drastic reduction from the ferry journey, which previously took over an hour.
Its upper deck carries the Seto-Chūō Expressway, with two lanes of motorway traffic in each direction. The lower level is dedicated to the Seto-Ōhashi Line, accommodating one railway line in each direction. The longest single section, the Minami Bisan-Seto Bridge, stretches for 1,100 metres.
Beyond its practical use, the bridge has become a major tourist draw. Enthusiasts and sightseers flock to vantage points like the Seto Ohashi Memorial Park to witness the structure, which the Japanese tourist board says "soars both into the sky and distance". The park itself offers gift shops, a rooftop viewing deck, Japanese gardens, and a playground. The spectacle is particularly breathtaking after dark when the bridge is illuminated.
Exploring the Connected Islands and Region
The bridge's route passes by several points of interest. Seijima, once an island, is now connected to Shikoku and is known for its sea bream fishing and cultural traditions. Shamijima, also now part of the mainland, boasts one of Japan's top 100 beaches and is home to the Memorial Park.
To the east, the Ogoshi district offers stunning views from the slopes of Goshikidai Mountain and is a hub for citrus farming. Once in Kagawa Prefecture on Shikoku, visitors can sample the region's famous Sanuki udon noodles, renowned for their chewy, thick texture.
How to Visit the Engineering Wonder
For travellers wishing to see this marvel, the simplest route is to fly into Tokyo and then take a train to Okayama. You can experience the bridge directly by train, bus, or car. The JR Marine Liner service runs from Takamatsu and Okayama. Buses to the Seto Ohashi Memorial Park depart from Sakaide Station and take around 20 minutes.
The Seto Ohashi Bridge stands as a powerful testament to human ingenuity, transforming regional connectivity while creating an enduring and majestic landmark against the stunning backdrop of the Seto Inland Sea.
