Japan from the Sea: Seafarers, Sea Roads and Myth as a Navigator's Map
Why do you have to look at the sea to understand Japanese history? Takahiro Mitsui, a Japanese philosopher born in 1991, writing every Friday from inside Japan and outside academia, answers from his own fieldwork on coasts, straits and ferry decks: because Japan is an island nation, the movements of people across the sea are the key to local belief and the acceptance of culture, and myth reads as a navigator's map. Seen from the sea, not from the capitals: the reading of a thinker alive today.
Why is Japan often described only through Yamato, Kyoto and Edo, and what does that hide?
Takahiro Mitsui's thesis (Japan seen from the sea, 2025-09-14): centering the island nation on the viewpoint of the land, and on Yamato, Kyoto and Edo, is the great obstacle to insight into Japan, and without taking in the movements of people on the historical sea we cannot see.
What has always been a great obstacle to insight into Japan is the habit of centering the island nation on the viewpoint of the land, and of centering it on Yamato, Kyoto, and Edo.
The impression of Japan as an island nation has grown so strong that such a view is hard to hold, but that is why I feel keenly that without taking in, beyond what we expect, the movements of people on the historical sea, we cannot see.
The view that the sea must be emphasized is still almost ignored in archaeology and history, but it has often been put forward by folklore studies, which rest mainly on fieldwork.
Why do you have to look at the sea to understand Japanese history?
Takahiro Mitsui's thesis (A mountain called an island, 2025-09-01): looking only at a part, the whole cannot be seen, and because Japan is an island nation the movements across the sea are the greatest factor in understanding local belief and the acceptance of culture.
Looking only at a part, the whole cannot be seen. Because Japan is an island nation, we must look at the sea.
That it is called an "island" though it is a mountain shows that Usa belief is at its essence a belief of the sea.
Ancient Japanese history is very complex, but as one key, you should be able to see that looking at what movements there were across the sea is the greatest factor in understanding local belief and the acceptance of culture.
Did ancient myths contain real geographical knowledge?
Takahiro Mitsui's thesis (Myth was a navigator's map, 2025-08-25): the crossing from Tokushima to Wakayama was the mythic landscape of early Japan and the frontline of ancient diplomacy, with Nushima, the island of creation, at its midpoint.
At the very midpoint of this route lies a crucial landmark: the small island of Nushima. I conducted fieldwork on Nushima some five years ago.
Floating roughly fifteen minutes by ferry off the southern tip of Awaji Island, this tiny outcrop is identified in the Kojiki and the Nihon Shoki as the mythic island of creation where the primordial deities Izanagi and Izanami first descended to give birth to the land.
The sea crossing from Tokushima to Wakayama was thus far more than a corridor of transport; it was the mythic landscape of early Japan and the frontline of ancient diplomacy and intercultural exchange.
Why was the sea between Tokushima and Wakayama so dangerous in ancient times?
Takahiro Mitsui's thesis (Myth was a navigator's map, 2025-08-25): where three currents converge the crossing has been feared since antiquity and demanded sophisticated mastery of navigation, and the hills of the Wakayama coast were once offshore islands guiding boats to the interior.
The point where these three distinct currents converge has been feared as a treacherous passage since antiquity. While the modern ferry completes the crossing in about two hours, navigating these waters in small wooden craft meant entrusting one's life to the whims of tide and tempest. It required an exceptionally sophisticated mastery of navigation on the part of the ancient sea peoples.
Today a broad plain extends inland, but for millennia much of this low-lying basin was submerged beneath the sea. The hills we see today were once offshore islands, essential markers guiding boats toward the interior.
Can place names prove who ruled an ancient land?
Takahiro Mitsui's thesis (A history that may be lost before it is read, 2025-08-24): the southern half of the Tokushima peninsula kept an independent power, the land of Naga, and the place names along its coast are the tongue of the ancient seafaring peoples, one of the clearest proofs that the Kaifu clan once ruled there.
The southern half of the peninsula long retained an independent power known as the land of Naga (Naga no Kuni).
Driving south along the coast from Tokushima City toward Kainan, one encounters place names that preserve the resonance of archaic speech: Naka, Hiwasa, Anan, Mugi, Shishikui, Nasa. Their unusual, melodic cadence sounds alien to modern ears, but it derives from the tongue of the ancient seafaring peoples. This linguistic presence offers one of the clearest proofs that the Kaifu clan once ruled here. What outlasts all else, after all, is the intangible culture embedded in words and place names.
What happens to history when a coast could be destroyed by an earthquake before anyone studies it?
Takahiro Mitsui's thesis (A history that may be lost before it is read, 2025-08-24): a keyhole-shaped tumulus found in Kainan in 2023 may force a reevaluation of the maritime peoples, but a Nankai Trough megathrust earthquake could level this coastline and set the debate back indefinitely.
In the autumn of 2023, however, preliminary archaeological surveys for highway construction uncovered several burial mounds atop a hill in Kainan—including a keyhole-shaped tumulus.
Even modest excavation and preservation here would force a reevaluation of the relationship between the coastal Kaifu clans and the Yamato court, serving as a powerful counterweight to the conventional historical neglect of maritime networks in ancient Japan.
If a Nankai Trough megathrust earthquake strikes and levels this coastline, the debate surrounding ancient Japan’s maritime peoples will be set back indefinitely—and the opportunity to illuminate their history may be lost forever.
Did the ancestors of the Japanese come only through the Korean Peninsula?
Takahiro Mitsui's thesis (Homogenization erases the neglected, 2025-09-13; Those of the sea and those of the heights, 2025-09-12): the peopling of the archipelago cannot be reduced to migration across the Korean Peninsula alone, a southern maritime corridor along the Kuroshio must also be taken into account, and Japanese historiography has neglected the decisive role of ocean currents and winds.
It implies that the peopling of ancient Japan cannot be reduced to the standard narrative of migration across the Korean Peninsula alone. A southern maritime corridor must also be taken into account: a path of seafaring tribes who mingled along the southern Chinese coast and touched land along the island chain from Southeast Asia through the Ryukyus and Amami, making landfall sporadically across southern Japan.
Standard historical accounts tend to fixate almost exclusively on routes crossing the Korean Peninsula, but the peopling of the archipelago involved far more diverse paths, not least from the south.
The southern drift theory is compelling, yet it has received little attention because Japanese historiography has routinely neglected the decisive role of ocean currents and prevailing winds.
Which places did the official history overlook, and why did they matter?
Takahiro Mitsui's thesis (The crossroads history overlooked, 2025-09-15): going up the Chikugo River from the Ariake Sea shows a route besides the usual Genkai route, and the sea cormorants of the cormorant fishing at Hita show the influence of the old sea tribes on the culture of the river basin.
It has long been said that the tribes who came to Japan crossed from the Korean Peninsula via Tsushima into the Genkai Sea, landed in northern Kyushu, and moved south. This time, following the Chikugo River in person, I saw that there was another route, not the Genkai route, which went upstream from the Ariake Sea.
On the Mikuma River at Hita, for example, the custom of cormorant fishing is handed down, and though it is a river, it uses sea cormorants, not river cormorants. This too plainly shows the influence of the old sea tribes on the culture of the river basin.
Essays to read
- Japan seen from the sea — Why look at Japan from the sea? Takahiro Mitsui argues centering it on Yamato, Kyoto and Edo hides the movements of people across water.
- A mountain called an island — What is the oldest layer of belief at major Japanese shrines? Belief follows sea routes, Takahiro Mitsui observes: Usa Jingu's inner shrine is a mountain called an island, a faith of the sea — Takahiro Mitsui's field report on the deep layers of Usa's faith.
- Myth was a navigator's map — Did ancient myths contain real geographical knowledge? Takahiro Mitsui's thesis: for ancient seafarers myth was practical knowledge, and the kuniumi stories mapped real islands and currents, with the small island of Nushima a stepping stone, read from the Tokushima-Wakayama ferry.
- A history that may be lost before it is read — Takahiro Mitsui's thesis: the district name Kaifu (海部) traces back to the Amabe, the ancient sea peoples (ama), and evidence of them lies along a Pacific coast an earthquake could level, so a history may be lost before it is read.
- Homogenization erases the neglected — What happens to the cultures and memories of small, forgotten peoples? Homogenization threatens to sink neglected Jomon customs in the south and the memory of the Hayato, Takahiro Mitsui warns — Tsukuyomi at Kushira and Takeminakata's alliance with a local chief.
- Those of the sea and those of the heights — What do ancient Japanese myths say about sea people and mountain people? Myth records a struggle between those sustained by the sea and those sustained by the heights, Takahiro Mitsui reads, behind an older faith — Yamasachihiko and Toyotama-hime, where sea and mountain were not yet separated.
- The crossroads history overlooked — Why was Hita an important town in Japanese history? The Chikugo river's crossroads, Hita among them, mattered before the emperors' history began, Takahiro Mitsui writes of overlooked places — the Izumo people's traces along the Chikugo River after the Transfer of the Land (kuniyuzuri).
- What the buried children tell — What do ancient child burials tell us about a society in crisis? Children buried with bronze bells signal a force never seen before redrawing the map of power, Takahiro Mitsui reads — and why the Yayoi buried their bronze bells.
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