The , or Seto-Ohashi Bridge, is a series of double deck bridges connecting Okayama and Kagawa prefectures in Japan across a series of five small islands in the Seto Inland Sea. Built over the period 1978 - 1988, it is one of the three routes of the Honshū-Shikoku Bridge Project connecting Honshū and Shikoku islands. At 13.1 km long, it ranks as the world's longest two-tiered bridge system.

Crossing the bridge takes about 20 minutes by car or train. The ferry crossing before the bridge was built took about an hour. The toll from Kojima, Kurashiki (Okayama Prefecture on the Honshū side) to Sakaide (Kagawa Prefecture on the Shikoku side) is ¥3,500, and vice-versa.

The bridges carry two lanes of highway traffic in each direction (Seto-Chūō Expressway) on the upper deck and one railway track in each direction (Seto-Ōhashi Line) on the lower deck. The lower deck was designed to accommodate an additional Shinkansen rail line in each direction.

History

The bridge's history dates back to 1889 when a member of the Prefectural Parliament, , suggested the idea of a Seto Ohashi Bridge. Okubo Jinnojo was born in a remote village of West Sanuki. At 23, Jinnojo became a village official. He said: "The 4 provinces of Shikoku are like so many remote islands. If united by roads, they will be much better off, enjoying the benefits of increased transportation and easier communication with each other." He envisioned and worked on several major road projects. He aired his idea for the Bridge in a speech made at the opening ceremony of the first railway in Shikoku between Marugame and Kotohira. While it took a century for his vision to become a reality, another of his ideas, mentioned in a drinking song he composed, was accomplished twenty years sooner:

I'll tell you, dear, don't laugh at me,

a hundred years from now, I'll be seeing you

flying to and from the moon in a space ship.

Its port, let me tell you, dear,

will be that mountaintop over there!

The bridge idea lay dormant for about sixty years. In 1955, after 171 lives were lost when a ferry wrecked in dense fog off Takamatsu, a safer crossing was deemed necessary. By 1959 meetings were held to promote building the bridge. Scientists began investigations shortly after, and in 1970 the Honshū-Shikoku Bridge Construction Authority was inaugurated. Work was postponed by the "oil shock" of 1973. In 1978 the Environment Assessment Report was published and construction got underway. The project took ten years to complete at a cost of $7 billion. 2,000 construction companies and about 13 million workers were employed. Although nets, ropes and other safety measures were employed, the lives of 13 workers were lost during the 10 years of construction. The bridge opened for traffic on April 10, 1988.

Named bridges

Six of the eleven bridges are separately named, unlike some other long bridge complexes like the San Francisco-Oakland Bay Bridge (two bridges and one tunnel). The other five bridges are viaducts. The six named bridges are:

• — A suspension bridge with a center span of 940 meters which connects Honshū with the island of Hitsuishijima. The 22nd largest suspension bridge in the world.
• and — Two identical cable-stayed bridges with center spans of 420 meters.
• — A continuous truss bridge with five spans and a total length of 847 meters.
• and — Two suspension bridges with a common anchorage between them. With center spans of 990 and 1,118 meters respectively they rank as the 19th and 11th largest suspension bridges.

Trivia

• A 6.8 meter tall Dodama-jishi guardian was placed in the Seto Ohashi Memorial Park in Sakaide.
• It is designed to withstand violent typhoons and severe earthquakes.
• The roadway of the Bisan-Seto Bridges is 93 m above sea level, above the fog on foggy days.
• 3,646,000 cubic meters of concrete and 705,000 tons of steel were used in construction.
• It is a sister bridge of the Golden Gate Bridge.
• The average height of each tower is 200 meters (658 feet).
• In the OVA anime Tenchi Muyo! Ryo-Ohki, the bridge was damaged in a crash landing involving Ryoko Hakubi and Ayeka Masaki Jurai. It appeared repaired at the beginning of the third OVA.
• The Javanese composer Gesang Martohartono wrote a song titled "Seto Ohashi", in the traditional kroncong style.

See also

• Akashi-Kaikyo Bridge
• Kurushima-Kaikyo Bridge

External links

• Honshū-Shikoku Bridge Authority homepage
• Seto-Ohasi Bridge at Honshū-Shikoku Bridge Authority