Naruto Bridge Opening Day

What Is Naruto Bridge Opening Day?

Every June 8th is "Naruto Bridge Opening Day" (大鳴門橋開通記念日, Ōnaruto-kyō Kaitsū Kinenbi) in Japan. On June 8, 1985, the Ōnaruto Bridge (大鳴門橋) — connecting Hyogo Prefecture's Awaji Island with Tokushima Prefecture's Naruto City across the Naruto Strait (鳴門海峡) — was officially opened to traffic. The bridge, part of the Honshu-Shikoku Bridge Project that aimed to connect Japan's main island with Shikoku, was a major engineering achievement and opened a new chapter in transport connectivity between the two islands.

The Ōnaruto Bridge

The Ōnaruto Bridge spans 1,629 meters across the Naruto Strait — one of Japan's most challenging marine environments, where the tidal flows between the Pacific Ocean and the Seto Inland Sea create powerful whirlpools (鳴門の渦潮, Naruto no Uzushio) that are among the world's largest tidal whirlpool phenomena. The bridge's design had to account for these powerful currents as well as earthquakes, typhoons, and the salt-laden marine environment. The bridge is a suspension bridge with a distinctive double-deck design — the upper deck carries road traffic, while the lower deck was designed (though never completed for the purpose) to eventually carry Shinkansen track.

The Naruto Whirlpools

The Naruto Strait's famous whirlpools — created by the tidal exchange between the Pacific and the Seto Inland Sea, which forces enormous volumes of water through the narrow strait twice daily — are a major tourist attraction viewable from the Ōnaruto Bridge's "Uzu no Michi" walkway. The whirlpools can reach up to 20 meters in diameter during spring tides and are one of the world's most impressive natural tidal phenomena.

The Honshu-Shikoku Bridge Project

The Ōnaruto Bridge was the first completed link of the three-route Honshu-Shikoku Bridge Project — eventually including the Seto Ōhashi Bridge (1988) and the Nishiseto Expressway "Shimanami Kaidō" (1999). Together, these three bridge systems transformed Shikoku's connectivity to Honshu, reducing travel times dramatically and enabling the economic and social integration of Japan's fourth-largest island with the national network.

Fun Facts

• Uzu no Michi: The "Uzu no Michi" (渦の道, Whirlpool Walkway) — a glass-floored walkway suspended beneath the Ōnaruto Bridge's roadway — allows visitors to look directly down at the famous Naruto whirlpools from a height of 45 meters above the water, an experience that has become one of Tokushima Prefecture's most popular attractions.
• Walking to Shikoku: The Shimanami Kaidō bridge route across the Seto Inland Sea is the only one of the three Honshu-Shikoku connections with pedestrian and cycling access — making it one of the world's great bicycle touring routes, connecting islands and bridges across 60 kilometers of Seto Inland Sea scenery.