At the southern tip of Awaji, the island ends in a narrow strait separating it from Shikoku — the second of the great islands the Kojiki gods are said to have borne. The strait is called the Naruto Strait, and it is famous for one specific phenomenon: twice a day, on the spring tides, when the difference in water level between the Pacific Ocean on one side and the Inland Sea on the other reaches its peak, the strait fills with whirlpools — some of them up to twenty meters across, the largest sustained natural whirlpools on Earth.
If the kuni-umi describes Izanagi and Izanami stirring the ocean with a spear, this is the place where, by tradition, the stirring is most visibly continuing.
What happened here
This is not, strictly, a Kojiki site. The text does not mention the Naruto Strait by name. But the imagery of the kuni-umi — the spear lowered into the brine, the stirring, the brine dropping back from the spear’s tip — has long been linked, by local Awaji and Shikoku tradition, to the Naruto whirlpools.
The connection is geographical rather than textual. The Naruto Strait is the narrow passage between Awaji (the first island borne by the gods) and Shikoku (the second). To stand at the strait and watch the whirlpools is, on this telling, to watch the same churning of water that the gods are said to have begun.
It is also, more practically, the boundary where the Kojiki Trail’s Awaji volume ends and where the next phase of the kuni-umi narrative — the bearing of Shikoku — would begin.
What you’ll actually see
The Awaji-side base for viewing the whirlpools is Fukura Port, on the island’s southern coast. The port is a working fishing harbor with a small ferry terminal and a large covered visitor complex — Uzushio Dome Nanairo-kan — housing the ticket office for Uzushio Cruises, which run replica-galleon and high-speed-cruiser boats out into the strait several times daily, timed to the tides.
A cruise from Fukura takes about seventy minutes round trip. The boats pass under the Onaruto Bridge and into the calmer water at the edge of the whirlpools, where vortices can be observed forming, swirling, and dissipating from a few meters away. Tickets at the time of writing are ¥2,500 for an adult, ¥1,200 for a child.
For visitors who would rather view the whirlpools from above than from a boat, there is a second option, but it requires crossing the bridge. The Uzu-no-Michi (渦の道) is a 450-meter glass-floored walkway suspended inside the bridge structure itself, on the Tokushima side of the strait. From its observation deck — forty-five meters above the water — you can look directly down into the whirlpools as they form. Admission is ¥510 for adults. The walkway is open 9:00 AM – 6:00 PM in summer and 9:00 AM – 5:00 PM in winter, and is closed on the second Monday of March, June, September, and December.
Whirlpools form on every tide, but their size depends on the tidal differential. The largest occur during the spring tides (the highest tides of the lunar cycle), particularly in the equinoctial months of March, April, September, and October. On those days, vortices can reach twenty meters across and last for several minutes before dissipating. Check the tide table on the Uzushio Cruise or Uzu-no-Michi websites before visiting.
Three things to look for
- The maximum-tide schedule — published online by the cruise operators; plan your visit around it, as the difference between an off-tide and a peak-tide day is dramatic.
- The Onaruto Bridge — completed in 1985 to connect Awaji with Shikoku, visually striking from the boat tours, and one of the great pieces of late-twentieth-century Japanese infrastructure.
- The replica galleon Kanrin Maru — one of the two ships in the Uzushio Cruise fleet, a near-full-scale replica of the 1857 vessel that carried the first Japanese diplomatic mission to the United States. An unusual way to approach the whirlpools.
How it fits the trail
This is where the Awaji circuit closes. The Kojiki Trail’s Awaji volume begins at Iwaya Harbor in the north, follows the kuni-umi narrative south through Eshima, Onokoro Jinja, Izanagi Jingu, and Nushima with Kamitategami-iwa, and ends here, at the southern strait, where the act of creation that the trail describes is — still, twice a day — visibly continuing.
Stand on the deck of the cruise boat at peak tide, or on the glass floor of the Uzu-no-Michi. Watch the water turn beneath you. Then look back at Awaji.
You have walked the creation of Japan.