The Pacific Bermuda Triangle: Japan's Devil's Sea Explained

Where Is the Pacific Bermuda Triangle?

The Pacific Bermuda Triangle is a loosely drawn region of the western Pacific Ocean south of Tokyo. It goes by several names: the Devil’s Sea (in Japanese, Ma no Umi), the Devil’s Triangle, the Dragon’s Triangle and the Formosa Triangle. Its traditional centre is the Izu Islands, a volcanic chain that runs south from the Japanese mainland.

Pinning down its edges is harder than it sounds. The area has never appeared on any official chart, so every writer draws it differently. In 1955 the Japanese newspaper Yomiuri Shimbun described it as running from the Izu Islands to east of the Ogasawara (Bonin) Islands, roughly 200 miles from east to west and 300 miles from north to south. Later authors have drawn the area and its perimeter in different ways, and no single version has ever become standard.

That shifting shape is the first clue to how the legend works. A region without fixed borders can absorb almost any loss nearby. The same problem dogs its Atlantic counterpart, as our piece on the Bermuda Triangle on a map and why it shifts explains.

How the Devil’s Sea Legend Began

The phrase ma no umi was not invented for this stretch of water. It translates loosely as “devil sea”, “troublesome sea” or “dangerous sea”, and Japanese newspapers had applied it to hazardous waters all over the world for decades. Before 1954, the Asahi Shimbun alone used the label for places as far apart as the Bay of Bengal, the Kuril Islands, the Korea Strait, Lake Baikal, the Taiwan Strait and parts of the Atlantic. It was a journalist’s shorthand, not a place name.

The shorthand stuck to the waters south of Tokyo after one specific scare. On 4 January 1955, the ship Shinyo Maru No. 10 lost radio contact near Mikura-jima in the Izu chain. Japanese papers began calling the area a devil’s sea, and the Yomiuri Shimbun printed a map marking several other vessels lost in recent years, stating that they had gone down inside an area the Yokohama Coast Guard Office treated as a special danger zone. The paper counted nine ships lost in five years.

The story crossed the Pacific. In the United States, The New York Times covered the incident under the heading “The Devil’s Sea”, repeating the claim that nine ships had been lost there in perfect weather.

Then came the detail that tends to vanish from retellings: the Shinyo Maru No. 10 was found safe on 15 January 1955. The disappearance that launched the legend was not a disappearance at all.

Charles Berlitz and the Dragon’s Triangle

For nearly twenty years the Devil’s Sea remained a minor newspaper phrase. Its transformation into the Pacific Bermuda Triangle came from American paranormal writer Charles Berlitz, whose 1974 book The Bermuda Triangle introduced the region to Western readers as the Atlantic mystery’s Pacific counterpart.

According to Berlitz, nine modern ships and several hundred crew members vanished without a trace between 1950 and 1954. He wrote that in 1955 the Japanese government sent a vessel, the Kaiyo Maru No. 5, to investigate the losses, and that this ship disappeared too. After that, Berlitz claimed, Japanese authorities declared the sea a danger zone.

He returned to the subject in 1989 with The Dragon’s Triangle, claiming the region was also known by that name. In that book he added that five Japanese military vessels had disappeared while on manoeuvres near Japan’s shores in early 1942.

Other strange tales have attached themselves to the area over the years. One popular story says a Japanese Zero pilot crossing the region in August 1945 radioed that “something is happening in the sky... the sky is opening up” before going silent. The tale circulates in books of weird stories aimed at general readers, and no wartime record of the transmission is documented. It belongs with the legend, not the history.

Another writer, Daniel Cohen, wrote in his 1974 book Curses, Hexes & Spells that legends of the Dragon’s Triangle stretched back centuries in Japan. That claim would be easy to check if it were true, and it has not held up, as later sections show.

The Kaiyo Maru No. 5: The Legend’s Central Case

If the Pacific Bermuda Triangle has a flagship mystery, it is the Kaiyo Maru No. 5. In the popular version, a government research ship sails out to solve the riddle of the vanishing vessels and becomes the next victim, lost with everyone aboard.

The documented version is different, and in its own way more dramatic. The Kaiyo Maru No. 5 was a scientific research vessel sent to Myōjin-shō, an active submarine volcano in the Izu chain, to study its activity. It was lost with all hands on 24 September 1952, not in 1955. The ship was not chasing ghosts. It was studying a volcano, and the accepted explanation for its loss is that it was caught by an undersea eruption.

That shift in the date matters. Berlitz’s sequence, in which a series of unexplained losses prompts a government investigation that itself vanishes, only works if the research voyage came after the losses and was sent to explain them. Once the real date and purpose are restored, the story’s frightening logic falls apart.

What Larry Kusche Found When He Checked

In 1975, American author Larry Kusche published The Bermuda Triangle Mystery Solved, a case-by-case examination of the stories Berlitz and others had popularised. He gave the Devil’s Sea the same treatment he gave the Atlantic cases: he went looking for the original records.

Kusche wrote to government offices connected with the waters south of Japan. None of them knew of a Devil’s Sea or of any broad danger area matching the legend. What did exist was much smaller: the Maritime Safety Agency of Japan had warned vessels away from a zone about 10 miles around Myōjin-shō, the volcano. The large quadrangle printed in the newspaper was not the official danger zone.

His other findings chipped away at the remaining story:

• The ships were mostly small. Most of the nine vessels in the newspaper count were small fishing boats with poor radios or none at all.
• The weather was not perfect. The claim of losses in calm conditions did not match the record.
• Causes were known for some. Besides the Kaiyo Maru No. 5, at least one of the other eight losses had an identified cause.
• The area did not hold together. Two of the nine ships were lost near Miyake-jima and near Iwo Jima, roughly 750 miles apart, a spread that is hard to square with a region described as about 200 by 300 miles.

Decades later, skeptic writer Brian Dunning looked for evidence behind the claim of centuries-old Japanese legends about the Dragon’s Triangle. He reported finding no books, newspaper articles or magazine pieces about it until about twenty years after the Kaiyo Maru No. 5 was lost. In other words, the “ancient” legend appears to be a modern one, born in the 1950s press and built up in 1970s publishing.

Natural Explanations: Volcanoes, Gas and Rough Water

Skeptics point out that the waters south of Tokyo do not need a curse to be dangerous. The region is volcanically and seismically active, and the seafloor there is genuinely restless.

Undersea volcanoes

Submarine volcanoes are common in this part of the Pacific. Small islands here have a habit of appearing and disappearing through eruptions and seismic activity. A ship near an eruption faces violent water, floating debris and sudden changes in the sea itself. The Kaiyo Maru No. 5 is the clearest proof of how deadly this can be.

Methane hydrates

A more speculative explanation involves methane hydrates, ice-like deposits of gas trapped on the seabed. The idea is that chunks can break loose, rise and release gas at the surface, reducing the water’s density so a ship loses buoyancy and sinks quickly. The same proposal is often made for the Atlantic triangle. It remains a hypothesis: no specific loss in the Devil’s Sea has been tied to a gas eruption, and the theory is best treated as a possibility rather than an answer.

Ordinary maritime risk

The least exotic explanation may be the strongest. Small fishing boats with weak or no radios, working at sea in the early 1950s, in weather that was not always kind, faced real risk. When such a boat sinks, it can easily leave no trace and no final message, which looks mysterious only if you expect every loss to be explained.

Pacific Bermuda Triangle vs the Atlantic Bermuda Triangle

The two regions are linked mainly by one writer’s books, but comparing them shows how the same storytelling patterns repeat. The original Bermuda Triangle lies in the North Atlantic, between Bermuda, Puerto Rico and Florida. For more on that geography, see where the Bermuda Triangle is, its corners and myths.

One source of confusion is the name “Devil’s Triangle”, which has been applied to both regions. When people ask about the Bermuda Triangle and the Devil’s Triangle, they may mean the same Atlantic area or the Pacific one, depending on who is telling the story. Our look at whether the Bermuda Triangle is real covers how the Atlantic legend fared under the same kind of scrutiny, and what is actually inside the Bermuda Triangle walks through its seafloor and wrecks.

What Remains Unexplained, and Why the Legend Persists

It would be too neat to say every question about the Pacific Bermuda Triangle has been closed. Several of the nine ships in the 1955 count were never fully accounted for in the published record, and small vessels lost at sea in that era often left little paperwork behind. “Unexplained” in this sense means undocumented, not impossible. A fishing boat that vanished in 1953 may well have been swamped in bad weather, but nobody can prove it now.

There are also honest open questions about the region’s geology. How often submarine eruptions or seabed gas releases have affected passing ships, and how quickly the volcanic landscape changes, are real subjects of scientific interest, separate from any paranormal claim.

As for the legend itself, it endures for reasons that have little to do with evidence:

1. It has a famous twin. Presenting the Devil’s Sea as the Pacific version of a well-known mystery gave it instant credibility and a ready audience.
2. Retellings drop the corrections. The ship that turned up safe, the real date of the Kaiyo Maru loss and the true size of the danger zone rarely survive into online videos and listicles.
3. Fuzzy borders help. With no fixed map, any nearby loss can be counted as another victim.
4. Japan’s deep folklore is borrowed. Real traditions of sea spirits and dangerous waters make an invented “ancient legend” feel plausible, even when the trail starts in the 1970s.

That last point deserves care. Japanese maritime folklore is rich and genuine, but the specific idea of a cursed triangle south of Tokyo is a modern construction, as far as the record shows. For older traditions, our folklore and legends section is a better place to look.

The fairest way to read the Devil’s Sea

The strongest ordinary case is simple: a volcanically active stretch of ocean, worked by small and poorly equipped boats, produced losses that a newspaper bundled into a frightening label during a scare that ended happily. A popular writer then expanded the story and moved key dates. The strongest case for something stranger rests mostly on the gaps: losses with no recorded cause and a region whose reputation keeps returning.

Readers can weigh those for themselves. What the record does make clear is that the Pacific Bermuda Triangle is a story about how mysteries are made, as much as about the sea. For more on how legends like this grow, the conspiracy theories, examined section traces similar patterns, and long-form conversations about the unexplained live in the Troubled Minds Vault.

Questions and answers

Where is the Pacific Bermuda Triangle on the world map?

It sits in the western Pacific south of Tokyo, centred on the Izu Islands. In 1955 the Yomiuri Shimbun newspaper described it as running from the Izu Islands to east of the Ogasawara (Bonin) Islands, roughly 200 miles from east to west and 300 miles from north to south. Because it has never been plotted on any official chart, its boundaries vary from one writer to the next.

What is around the Pacific Bermuda Triangle?

The region holds the volcanic Izu island chain, including Miyake-jima and Mikura-jima, along with the Ogasawara Islands. Beneath the surface lie submarine volcanoes such as Myōjin-shō, and the area is seismically active. Small islands here have appeared and vanished through eruptions and earthquakes, which is part of why the sea has a dangerous reputation.

How many ships have gone missing in the Devil's Sea?

No reliable official total exists. In 1955 the Yomiuri Shimbun newspaper reported nine ships lost in five years, and Charles Berlitz later repeated that figure with dramatic additions. Author Larry Kusche found that most of those nine were small fishing boats, that two were lost roughly 750 miles apart, and that at least two losses had known causes, including an undersea eruption.

Has anyone survived the Pacific Bermuda Triangle?

Yes, and the most famous example helped start the legend. In January 1955 the Shinyo Maru No. 10 lost radio contact near Mikura-jima, prompting Japanese newspapers to call the area a devil's sea. The ship turned up safe eleven days later. That episode shows how a lost radio signal can be mistaken for a disappearance, and how quickly a scare can harden into legend.

Is the Devil's Sea the same as the Bermuda Triangle?

No. The Bermuda Triangle lies in the North Atlantic between Bermuda, Puerto Rico and Florida, while the Devil's Sea is in the western Pacific south of Japan. They are linked because writer Charles Berlitz introduced the Devil's Sea to Western readers in his 1974 book The Bermuda Triangle, presenting it as a Pacific twin with similar unexplained losses.

Can you swim in the Bermuda Triangle?

Yes. Both the Atlantic Bermuda Triangle and the Pacific Devil's Sea are ordinary stretches of ocean with no special hazard to swimmers beyond the usual ones: currents, weather and distance from shore. Bermuda, Puerto Rico and Florida sit at the Atlantic triangle's corners. Anywhere at sea, local conditions and safety advice matter far more than any legend.

Stay curious. Keep the question open.
Follow the evidence wherever it leads.