神話の宿る古代の海Ancient Sea Where Myths Reside

Today I boarded a ferry from Tokushima Port, crossed to Wakayama Port, and then traveled on to Osaka for some errands. This maritime route linking Tokushima and Wakayama is one that I had long been interested in, because when considering how local people in Shikoku came into contact with the centralized royal authority of Yamato in ancient times, the existence of this sea route and the seafarers who traversed it holds immense significance.

This sea area receives the flow of the Yoshino River, the largest river in Shikoku, into Tokushima, while to the northwest spreads the Naruto Strait adjoining Awaji Island. Beyond lies Wakayama Prefecture across the Tomogashima Channel, and further south extends the broad Kii Channel. The convergence of these three powerful currents has been known since antiquity as a “perilous sea.” While today’s ferry makes the crossing in about two hours, in ancient times navigating these waters in small boats meant a journey at the mercy of weather and tides, a life-threatening undertaking that clearly required highly advanced maritime skills possessed by seafarers.

Looking out from the deck, one realizes that although the waters seem surrounded by islands, a light haze quickly causes island silhouettes to fade, melting into the horizon and obscuring direction. Ancient voyagers surely witnessed the same scenes, and their cautious navigation can easily be imagined.

Most important along this route is the small island of Nushima, located roughly at the midpoint. I conducted research there about five years ago. Situated fifteen minutes south by ferry from the southern tip of Awaji Island, this small island is described in the Kojiki and Nihon Shoki as the “Island of Creation” where Izanagi and Izanami first descended in the myth of the birth of the land. In antiquity it was called Onokoro-shima (淤能碁呂島), and even today the Onokoro Shrine stands there. Rising from the sea is the sacred Kamitatekami-iwa, a giant rock said to be tied to the myth itself, piercing the sky and forming a mysterious landscape. Viewed from the sea, Nushima appears with the ridgeline of the Yuzuruha Mountains of Awaji silhouetted behind, presenting nothing less than the stage of myth itself.

Continuing the voyage, one sees the eastern tip of Awaji’s southern coast, Oshikibana, along with Kada Cape on the Wakayama side, with Jinoshima and Tomogashima lying in between. On the Tokushima side flowed the Yoshino River, but on the Wakayama side the mighty Kinokawa River empties into the sea, with the vast Kii mountain ranges towering in the background. What draws attention along the Wakayama coastline are the small hills visible from the sea. Today these areas are expansive plains, but in ancient times they remained covered by the sea, making those small hills function as important offshore islands that guided entry inland. To ancient seafarers, the coastal scenery of Wakayama would have appeared like an archipelago, dotted with countless islets.

What we must especially consider is how ancient people from Shikoku approached Yamato. Before entering land that was still unknown to them, it is likely they first landed on nearby small islands to survey the terrain and observe conditions before venturing onto the mainland. Since these regions had been inhabited since the Jomon period, a sudden incursion onto the mainland would have carried serious risk.

Therefore, small islands served as safe markers and temporary bases, where what we might today call envoys or diplomats were sent ashore to conduct negotiations or rituals with local groups. Only after such exchanges would they proceed to enter the mainland. This practice of “using small islands as stepping stones” seems directly reflected in the mythic setting of the kuniumi (国生み, birth of the land), and for ancient seafarers it must have been essential knowledge.

Thus, the sea route from Tokushima to Wakayama was not merely a path of transport but a stage of Japanese mythology and a gateway of ancient diplomacy and exchange. The scenery viewed from the ferry deck overlaps with the sea once crossed at the cost of life by our ancestors, making one feel vividly how myth and history continue to live on in the present.