The Vortex of Myth and Legend
A long time ago, the gods dwelt in the heavens above the blue skies of earth. One day, the gods Izanagi and Izanami stood atop a bridge and saw the land drifting aimlessly like a drop of oil upon the primeval ocean. The pair then brought the celestial spear Amenonuboko down upon the world and began churning the seas with all their might.
The beginning of the “Kojiki,” the oldest history book in all of Japan, tells of great primordial “vortexes.” This points to the whirlpools of the Naruto Strait. To catch sight of them, we encourage you to board the Uzushio Cruise off of Fukura Port on Awaji Island. You will travel under the Ōnaruto Bridge, where you will see said whirlpools churning the water’s surface. As the vortexes swirl on top, the waters taper deep down into the ocean. It’s a wondrous sight, as if some unseen hand was stirring the waters along.
This "hand" comes from the moon itself. The moon’s gravity pushes and pulls the seas twice a day, causing the high and low tides. At high tide, the currents on the Pacific side of the Naruto Strait pass through the Akashi Strait, revolving counterclockwise around Awaji Island until they finally arrive at the Setouchi side of the Naruto Strait, six hours later. By this time, the Pacific side is approaching low tide, and the dramatic change in the sea levels creates intense currents. The Naruto Strait is narrow but cuts deep to the bottom of the ocean; its central currents soon clash at both ends with Shikoku and Awaji Island, dampening their force. The differing speeds of the adjoining currents create “gaps,” which in turn cause whirlpools to form in succession.
The Naruto whirlpools are largest during the Full and New moon. At a staggering 26 meters in diameter, they are some of the largest on Earth. Considering that it takes precisely six hours for them to lap around Awaji Island, one gets a sense of the size of the island itself. Add to that the extremely narrow Naruto Strait, at 1.3 kilometers, and its V-shaped submarine topography, and you have all the elements for the creation of gigantic whirlpools.
They taper neatly to the bottom of the sea, resembling sharp cones. If one looks intently they may feel as if they’re getting sucked in. Nutrients are hoisted to the surface by the whirlpools,which provides essential sustenance to marine life. As such, whirlpools are not only the cradle of life, in a mythological sense, but they continue to provide the sea’s bountiful harvest to this day.
