March 10, 1985
A major breakthrough – both literal and figurative – took place for the construction of the Seikan Tunnel in Japan when the entire tunnel was finally opened from one end to another. This long-awaited boring through of the tunnel was made possible after Tokuo Yamashita, Japan’s minister of transport, detonated a dynamite charge that blasted away the last remaining earth along the route of the planned structure. The Associated Press reported, “Moments later, light poured through the other side of the 33.39-mile [53.74-kilometer]-long Seikan tunnel between the main Japanese island of Honshu and the northern island of Hokkaido.” The detonation was done on the Hokkaido side.
The Seikan Tunnel, which courses beneath the Tsugaru Strait (a body of water connecting the Sea of Japan with the Pacific Ocean), now provides a vital transportation link between Honshu and Hokkaido. While such a link was given serious consideration as far back as during the reign of the Japanese Emperor Taishō between 1912 and 1925, the need for the tunnel grew all the more urgent a few decades later due to several major developments. These developments included the ever-increasing traffic between both islands and also a 1954 typhoon that sank five ferries in the Tsugaru Strait and led to the deaths of 1,430 passengers, highlighting the stark danger and deficiencies of overreliance on maritime transportation options.
Construction on the Seikan Tunnel ultimately commenced in 1971. About a year-and-a-half after the dynamite charge set off by Yamashita fully cleared the last existing obstruction for the tunnel, an electrified rail system was installed within the structure. The tunnel was officially opened to rail traffic on March 13, 1988.
More than 14 miles (22.5 kilometers) of the Seikan Tunnel is beneath the water, making it the world’s longest tunnel with an undersea segment. (While it has a total length of only 31.4 miles [50.5 kilometers], the Channel Tunnel connecting the United Kingdom with France has a longer undersea section of 23.5 miles [37.9 kilometers]). The Seikan Tunnel also has the distinction of being second only to Switzerland’s Gotthard Base Tunnel, which has a route length of 35.5 miles (57.1 kilometers), as the longest mainline railway tunnel now in existence.
For more information on the Seikan Tunnel, please check out https://www.atlasobscura.com/places/seikan-tunnel.