The Dragon’s Triangle is a stretch of the Pacific south of Tokyo that has been called the Devil’s Sea, the Formosa Triangle and the Bermuda Triangle of the Pacific. The story most people know says ships and planes vanish there without trace, that Japan declared it a danger zone and stopped sending research vessels, and that the sea has been feared for centuries.
Almost none of that survives contact with the record. What the record does contain is more interesting than the legend: a submarine volcano that built an island, destroyed a government survey ship and was heard by underwater microphones in California; the largest British ship ever lost at sea; a new island that appeared in 2013 and has kept growing; and a paper trail showing exactly when, and by whom, the “mystery” was written.
This list is in three parts. The first is what the record shows. The second is how the legend was built. The third is the claims that circulate most widely and do not hold up, with what the sources actually say.
The Dragon's Triangle on video
Part 1: What the record shows
1. Where the Dragon’s Triangle actually is
There is no official boundary, because no government or hydrographic office has ever drawn one. The area named in the Japanese press in 1955 ran from the Izu Islands south to the east of the Ogasawara (Bonin) Islands, about 200 miles east to west and 300 miles north to south. Later authors stretched it into a triangle with corners at Taiwan, the volcanic island of Miyake-jima south of Tokyo, and Iwo Jima. Which version you see depends on which book the map was copied from. The one thing the versions share is the Izu–Bonin volcanic chain running down the middle.
2. “Ma no umi” is a phrase, not a place
The Japanese term behind “Devil’s Sea” is ma no umi, which translates as devil sea, troublesome sea or dangerous sea. Japanese newspapers used it as an ordinary description for hazardous water long before anyone applied it south of Tokyo. The Asahi Shimbun archive has it attached to the Bay of Bengal in 1914, the Kuril Islands in 1924, the Korea Strait and Lake Baikal in 1926, the coast off Hainan in 1939, the Atlantic in 1940 and the Taiwan Strait in 1954. The name proves that sailors thought a patch of water was dangerous. It does not name a single patch.
3. January 1955: the ship that started the name
On 4 January 1955 the fishing vessel Shinyo Maru No. 10 lost radio contact near Mikura-jima in the Izu Islands. Japanese newspapers began calling the area ma no umi, and the Yomiuri Shimbun printed a map plotting other vessels lost nearby in recent years. The New York Times picked the story up under the headline “Devil’s Sea”, reporting nine ships lost in perfect weather. On 15 January the Shinyo Maru was found, safe, with everyone aboard. The name outlived the scare that produced it.
4. The nine lost ships, examined
The “nine ships lost in five years” figure is real and comes from the 1955 Yomiuri map. Larry Kusche, who investigated it in 1975, found that most of the nine were small fishing boats with poor radios or none, that the weather at the time of the losses was not perfect, and that two of the nine went down near Miyake-jima and Iwo Jima respectively, about 750 miles apart. Two of the nine were fully accounted for. One of them is the next entry.
5. 24 September 1952: Kaiyo Maru No. 5
The one genuinely famous loss is a Japanese government ship. Kaiyo Maru No. 5, a survey vessel of the Hydrographic Department of the Maritime Safety Agency, was sent to observe a new submarine eruption at Myōjin-shō, about 450 km south of Tokyo. On 24 September 1952 the volcano erupted beneath or beside the ship and destroyed it, killing all 31 people aboard, including nine scientists. Debris was later recovered. The loss was a national tragedy and it was never a mystery: the ship was studying an erupting volcano and the volcano erupted.
6. Myōjin-shō, the volcano that built and lost an island
Myōjin-shō is a submarine volcano on the Izu–Ogasawara Ridge whose activity has been recorded since 1869. Its 1952–53 eruption was one of the largest on record there. It repeatedly raised a small island above the surface, at one point several tens of metres high, and repeatedly blew it apart, until the island sank for good after a major eruption in September 1953. The name comes from the fishing boat No. 11 Myōjin-Maru of Yaizu, whose crew were the first to witness the 1952 eruption.
7. The eruption was heard in California
On 18 September 1952 the US Navy’s SOFAR hydrophone stations at Point Sur and Point Arena, California, recorded strong, unusual underwater signals. The Hawaii station heard nothing, which placed the source west of the date line, and a line of position from the two California stations passed about 200 nautical miles south of Tokyo. Once news of the Myōjin-shō eruption arrived, the recordings were matched to the volcano and used to pin down the most likely time Kaiyo Maru No. 5 was destroyed. Dietz and Sheehy published the work in the Geological Society of America Bulletin in 1954. It was the first time a volcanic eruption had been correlated with SOFAR signals.
8. The only danger zone Japan ever declared
Berlitz wrote that after the Kaiyo Maru loss “Japanese authorities have labeled the sea as a danger zone.” Kusche wrote to the Japanese agencies responsible for the area and none of them knew of a Devil’s Sea or any such zone; the 1955 Yomiuri map had spoken of a Yokohama coast guard “special danger area”, and that is what he was tracing. What the Maritime Safety Agency had actually done was warn shipping to stay roughly ten miles clear of Myōjin-shō while it was erupting. That is a warning about one active volcano, not a region.
9. Japan did not stop surveying; it built a robot
The legend says Japan abandoned research in the area after 1952. The opposite happened. After losing Kaiyo Maru No. 5 the Hydrographic Department developed Manbou (“sunfish”), an unmanned, radio-controlled survey boat for dangerous waters such as active submarine volcanoes. In 1998 and 1999 the Department ran comprehensive seabed surveys around Myōjin-shō with the survey vessel Shoyo and the second-generation Manbou II, which worked the innermost three nautical miles on preprogrammed instructions. Those surveys produced the first detailed map of the seafloor there.
10. What the 1998–99 survey found
Myōjin-shō had been thought to be the central cone of a double volcano, with the nearby Bayonnaise Rocks as part of its rim. The surveys showed both Myōjin-shō and the Bayonnaise Rocks are cones sitting on the rim of a single large caldera volcano. Its base lies 1,400 to 1,500 metres down and measures about 30 by 25 kilometres; the caldera floor is 5.6 kilometres across and about 1,100 metres deep. Myōjin-shō itself is a cone about 550 metres tall whose summit comes within about 50 metres of the surface. Gas bubbling near the summit and micro-earthquakes showed it was still active at a low level.
11. The Bayonnaise Rocks
The rocks that mark the eruption site above water are the Bayonnaise Rocks, which rise about 10 metres above sea level. They take their name from a nineteenth-century French naval vessel, the Bayonnaise. On a calm day they look like nothing at all: a few dark teeth of rock in open ocean, 450 km from Tokyo. The volcano underneath them is the size of a small mountain range.
12. A volcanic arc running from Tokyo to Guam
The reason the region is full of volcanoes is that it sits on the Izu–Bonin–Mariana arc, where the Pacific Plate dives beneath the Philippine Sea Plate. The arc runs more than 2,500 km from the Izu Peninsula south through the Izu Islands, the Ogasawara Islands and Iwo Jima to the Mariana Islands and Guam. The inhabited Izu Islands are volcanoes, several have erupted within living memory, and the seafloor between them carries dozens more that never break the surface.
13. Nishinoshima: an island appeared in 2013 and is still there
The claim that islands “appear and disappear” in the region sounds like legend and is simply true. In November 2013 an eruption off the tiny island of Nishinoshima in the Ogasawara group raised a new islet above the sea. By late December 2013 it had merged with the original island (the Japan Coast Guard announced the join on 26 December). Lava flows through 2014 overran almost all of the old island, and by the end of that year the new Nishinoshima covered about 2.3 square kilometres and rose about 100 metres. Further eruptions followed in 2017, 2018, 2019–20, 2021, 2022 and 2023, and biologists have been watching how birds and plants colonise a landmass younger than most of the people reading this.
14. Miyake-jima: an island evacuated for four and a half years
Miyake-jima, the island most often used as the triangle’s northern corner, is a stratovolcano about 180 km south of Tokyo. Its summit, Mount Oyama, has erupted 13 times in the last 500 years; a 1940 lava flow killed 11 people. On 8 July 2000 a new series of summit eruptions began (the unrest had started with an earthquake swarm and a small submarine eruption off the west coast on 26 and 27 June), and by September the entire island had been evacuated. Sulphur dioxide kept pouring from the mountain for years, and residents were not allowed home permanently until 1 February 2005. For a time after their return they were required to carry gas masks. Flights to Tokyo did not resume until 2008.
15. Aogashima: living inside a volcano
South of Miyake-jima is Aogashima, an inhabited island that is a volcano within a volcano: a smaller cone sits inside the larger caldera. The Japan Meteorological Agency’s catalogue records the sequence: hot water and crater activity in 1780, ashfall in 1781, and in April 1783 incandescent blocks that burned 61 houses and killed seven people, followed by lava flows through 1785. The great eruption of April and May 1785 killed 130 to 140 of the 327 islanders; the rest were evacuated to Hachijō-jima and the island stayed devastated for more than fifty years. Around 170 people live there today, the smallest population of any municipality in Japan, on an island the Japan Meteorological Agency still lists as an active volcano.
16. Torishima, 1902
Further south still is Torishima, an uninhabited volcanic island best known as a breeding ground of the short-tailed albatross. The island was settled in the Meiji period by feather and guano collectors; an estimated five million albatrosses were killed there, and by 1933 about 50 birds were left. In August 1902 the volcano erupted and killed all 125 residents (contemporary reports put the toll at 150). The island was resettled, evacuated again when the volcano erupted in 1939, and has been deserted since the weather station set up in 1947 was closed on 16 November 1965 after an earthquake swarm. It is now a protected sanctuary that only researchers may land on.
17. Fukutoku-Oka-no-Ba, 2021: a pumice raft the size of a city
On 13 August 2021 the submarine volcano Fukutoku-Oka-no-Ba, five kilometres from South Iwo Jima, erupted with a plume that the Smithsonian’s Global Volcanism Program records at up to 16 km high. Within two days it had built a new island about a kilometre across. By a Japan Coast Guard overflight on 26 August the eastern part had mostly eroded into two small islets, and by 12 September the eastern side had gone under entirely. The eruption also released a vast raft of floating pumice, which by early October had drifted more than 1,000 km to the Daito and Ryukyu Islands, where it filled 16 fishing ports in Okinawa and Kagoshima, damaged about 40 boats and took weeks to clear. The volcano had built and lost ephemeral islands before, in 1904, 1914 and 1986.
18. The deepest water on Earth is just to the south
The arc is flanked by some of the deepest trenches in the world. The Izu–Ogasawara Trench, east of the islands, reaches depths of more than 9,000 metres, and it joins the Mariana Trench to the south, whose Challenger Deep, at roughly 10,900 metres, is the deepest known point in any ocean. Anything that sinks in this water goes a very long way down, which has a practical consequence: wrecks here are rarely found, not because they vanish, but because searching at those depths was impossible for most of the twentieth century.
19. The Kuroshio Current
The Kuroshio, the Pacific’s counterpart to the Gulf Stream, flows northeast past the Izu Islands carrying warm water from the tropics toward Japan. It is one of the strongest ocean currents in the world, its path meanders from year to year, and where it meets colder water it produces sharp changes in sea temperature over short distances. The old version of this page called that “erratic water temperatures” and treated it as an anomaly. It is the normal behaviour of a western boundary current, and it is one reason the region has such rich fisheries, which is why so many small boats were out there in the first place.
20. Typhoon Alley
The northwest Pacific is the most active tropical-cyclone basin on Earth, and the waters south of Japan sit squarely on the track typhoons follow as they curve north and east. That is the single most important fact about ship losses in the region, and it appears in almost none of the legend versions. A fishing boat with no radio caught by a typhoon in 1952 did not need a vortex to disappear.
21. MV Derbyshire, 1980: the largest British ship ever lost
On 9 September 1980 the ore carrier MV Derbyshire, 294 metres long and carrying 157,446 tonnes of iron ore from Canada to Kawasaki, hove to in Typhoon Orchid about 230 miles from Okinawa, in the Philippine Sea south of Japan. She sank with all 42 crew and two of their wives, and sent no mayday. A search found nothing and was called off after six days; one lifeboat turned up six weeks later. At 91,655 gross tons she remains the largest British ship lost at sea. For fourteen years she was exactly the kind of story the legend feeds on.
22. Derbyshire found and explained
In June 1994 a deep-water search found the wreck four kilometres down, spread across 1.3 km of seabed. An expedition spent more than 40 days photographing the debris field, and the formal investigation established the sequence: waves sheared the covers off small ventilation pipes at the bow, seawater flooded the forward spaces over two days, the bow rode lower and lower, and the first cargo hatch buckled inward under the sea, followed by the second and third. The crew were cleared of any responsibility. A later independent assessment by Douglas Faulkner of the University of Glasgow linked the loss to the then-emerging science of freak waves and concluded she was almost certainly destroyed by a rogue wave. A mystery, then a wreck, then an engineering finding: that is the pattern for every loss in this region that has ever been properly investigated.
23. Methane hydrates: a real deposit and an untested explanation
One “scientific” explanation that circulates is that methane hydrate, an ice-like deposit in the seabed, breaks loose, rises as a mass of bubbles and sinks ships by destroying the water’s buoyancy. The deposits are real; the seabed off Japan holds large fields of them. The sinking mechanism was demonstrated with a model hull in a tank in experiments reported in 2003, and the same researchers pointed to a wreck lying in a hydrate crater in the North Sea as a possible real case. No such eruption has ever been observed at sea, and no ship loss has been proven to have happened this way, in the Devil’s Sea or anywhere else.
Part 2: How the legend was built
24. 1971: Ivan Sanderson invents the “vile vortices”
The Devil’s Sea as a paranormal region begins with Ivan T. Sanderson, a biologist turned cryptozoologist best known for Bigfoot investigations. In the April 1971 newsletter of his Society for the Investigation of the Unexplained, and again in Saga magazine in August 1972 under the title “The Twelve Devil’s Graveyards Around the World”, Sanderson proposed twelve “vile vortices” spaced around the globe, including the two poles, the Bermuda Triangle, and a Pacific triangle south of Japan. The pattern was a geometric idea, not an observation: he placed five triangles evenly around the Tropic of Cancer and five around the Tropic of Capricorn.
25. 1974 and 1989: Charles Berlitz names it
The Atlantic legend already had a print history: an Associated Press feature in 1950 had asked why ships and planes went missing off the Florida coast, and Vincent Gaddis coined “Bermuda Triangle” in 1964. Its Pacific twin had none. Charles Berlitz researched parts of his 1974 bestseller The Bermuda Triangle at Sanderson’s farm, and the book introduced the Devil’s Sea to a mass audience alongside the Atlantic legend. Berlitz claimed nine modern ships and “several hundred” crew were lost without trace between 1950 and 1954, and that a government expedition sent to investigate in 1955 vanished too. In 1989 he gave the region its own book, The Dragon’s Triangle, and its now-standard name. Almost everything on the older version of this page traces back to those two books.
26. 1975: Larry Kusche checks the sources
Librarian Larry Kusche went to the primary sources for The Bermuda Triangle Mystery: Solved (1975). For the Devil’s Sea he wrote to the Japanese offices responsible for the waters, examined the 1955 newspaper coverage and the Yomiuri map, and found that the “government expedition” was the Kaiyo Maru No. 5, sent to study a volcano in 1952 and destroyed by it; that most of the nine ships were fishing boats; and that the losses were spread across an area far larger than any triangle. In a later Skeptical Inquirer article he showed the “military vessels” Berlitz listed in 1989 were fishing boats too, some of which sank outside the region as Berlitz himself defined it.
27. The paper trail has a start date
Brian Dunning of Skeptoid searched for any reference to the Devil’s Sea, or any of its other names, in books, newspapers and magazines in English and Japanese before the early 1970s, and found nothing. Nearly every published reference clusters immediately after Sanderson’s 1971–72 articles and Berlitz’s 1974 book. The claim that the region “has been feared for centuries” is repeated by Berlitz and by Daniel Cohen’s 1974 Curses, Hexes and Spells, and no earlier source for it has ever been produced.
28. Yamatai is a video game
Several online versions of the legend, including the old version of this page, map the triangle around an island called Yamatai. That island exists in Tomb Raider (2013), where it is the fictional setting for the whole game, placed by the game’s writers inside the Dragon’s Triangle. Yamatai is also a real name: it is what third-century Chinese chronicles called the realm of the Japanese queen Himiko, whose location historians still argue about. It is not an island in the Philippine Sea, and the map that circulates with the legend was drawn for a game.
Part 3: Claims that do not hold up
29. “Kublai Khan’s fleets were destroyed in the Dragon’s Triangle”
The Mongol invasions of 1274 and 1281 are real, and both fleets were wrecked by storms, the second by the typhoon the Japanese called kamikaze, the divine wind. But the fleets sailed from Korea and southern China and attacked Hakata Bay on Kyushu; the 1281 fleet was destroyed at anchor off Takashima and in Imari Bay, on the far western side of Japan, roughly 900 km from the Izu Islands. Underwater archaeologists found a Yuan-dynasty wreck off Takashima in 2011. Nothing about the invasions touches the Devil’s Sea, and the legend borrowed them for the same reason it borrowed everything else: they are a famous Pacific disaster with a storm in it.
30. Flight 19, Amelia Earhart, “100 scientists” and the antipode
Four more claims from the old page, corrected. Flight 19, the five US Navy Avengers lost in December 1945, disappeared off Florida in the Atlantic; it is the founding story of the Bermuda Triangle and has no connection to the Pacific. Amelia Earhart vanished in 1937 near Howland Island in the central Pacific, thousands of kilometres from Japan. Kaiyo Maru No. 5 carried 31 people, not the 100 scientists some retellings give it. And the Devil’s Sea is not “diametrically opposite” the Bermuda Triangle: the point on the globe opposite Bermuda lies in the Indian Ocean off Western Australia. The two regions sit in the same latitude band, about 25 to 32 degrees north, which is the band typhoons and hurricanes share. That is a coincidence of climate, not geometry.
What is left when the legend is removed
A volcanic arc, a typhoon track, one of the world’s strongest currents, some of its deepest water, and a fishing fleet that worked all of it in small wooden boats with no radios for most of the twentieth century. Ships were lost there because ships are lost in places like that. The one loss everyone cites, Kaiyo Maru No. 5, has the best-documented cause of any in the list, down to underwater recordings made some 8,600 km away.
If it is sea mythology you are after, Japanese folklore does have a sea-dragon: Ryūjin, the dragon king who rules the ocean from a palace beneath the waves and controls the tides with jewels. He appears in the same stories as the gods of death and the underworld from other traditions, and he is a far better story than a vortex. And if what draws you to the Devil’s Sea is the idea of the ocean doing something strange, the rare cloud formations that form over water like this, from roll clouds to fallstreak holes, are strange, photographable and real.
Sources
Kusche, L., The Bermuda Triangle Mystery: Solved (Harper & Row, 1975), pp. 252–260 · Kusche, L., “The Dragon’s Triangle”, Skeptical Inquirer · Berlitz, C., The Bermuda Triangle (Doubleday, 1974), pp. 91–92; The Dragon’s Triangle (Wynwood, 1989) · Dunning, B., “The Bermuda Triangle and the Devil’s Sea”, Skeptoid #337, 20 Nov 2012 · Dietz, R. S. and Sheehy, M. J., “Transpacific Detection of Myojin Volcanic Explosions by Underwater Sound”, GSA Bulletin 65 (1954) · Yashima, Nishizawa and Ootani, “The Survey of Myojin-Sho, the Submarine Volcano, by Unmanned Radio Operating Boat Manbou-II”, FIG 2001 · Smithsonian Global Volcanism Program entries for Myojinsho, Nishinoshima, Miyakejima, Fukutoku-Oka-no-Ba · Japan Coast Guard bulletins on Nishinoshima, 2013–2021 · UK formal investigation into the loss of MV Derbyshire (2000); Faulkner, D., “Rogue Waves: Defining Their Characteristics for Marine Design” (2000) · New York Times, 16 Jan 1955, “Tokyo Gets News From Missing Ship” · Yomiuri Shimbun, 14 Jan 1955.
Image credits
Public-domain and CC0 files are used without attribution requirement. The following are used under Creative Commons or Government of Japan Standard Terms of Use licences: Izu-Oshima 20031104-2.jpg by Japan Coast Guard, Attribution (Government of Japan Standard Terms of Use), via Wikimedia Commons; Mikura-jima.jpg by Izawa Ryu, CC BY-SA 4.0, via Wikimedia Commons; Kogawa fishing port Yaizu city.jpg by Akahito Yamabe, CC BY-SA 4.0, via Wikimedia Commons; Point Sur Lighthouse (5063709302).jpg by Bjorn, CC BY-SA 2.0, via Wikimedia Commons; Bayonnaise Rocks 20150818.jpg by Japan Coast Guard, Attribution (Government of Japan Standard Terms of Use), via Wikimedia Commons; Japan Coast Guard HL01 SHOYO.jpg by U-310, CC BY-SA 3.0, via Wikimedia Commons; Bayonaise Rocks mlit.jpg by MLIT (国土交通省), Attribution (Government of Japan Standard Terms of Use), via Wikimedia Commons; Bayonnaise Rocks 20020904.jpg by Japan Coast Guard, Attribution (Government of Japan Standard Terms of Use), via Wikimedia Commons; Ioto Island Location Map Ueda et al 2018 R1.jpg by Ueda et al. 2018, CC BY 4.0, via Wikimedia Commons; Miyakejima O-Yama Volcano crater.jpg by さかおり, CC BY-SA 4.0, via Wikimedia Commons; Aogashima 20130701.jpg by Japan Coast Guard, Attribution (Government of Japan Standard Terms of Use), via Wikimedia Commons; Torishima 20250515 113135.jpg by Ka23 13, CC BY 4.0, via Wikimedia Commons; Western Boundary Currents – The Kuroshio Current.jpg by NASA Goddard Space Flight Center, CC BY 2.0, via Wikimedia Commons; MV Derbyshire memorial 2.jpg by Rodhullandemu, CC BY-SA 4.0, via Wikimedia Commons; Wasser über Deck und Luken WNA.png by Buonasera, CC BY-SA 3.0, via Wikimedia Commons; Bayonnaise Rocks 20120825.jpg by Japan Coast Guard, Attribution (Government of Japan Standard Terms of Use), via Wikimedia Commons; Map of the world with Dragon Triangle and Bermuda Triangle location.jpg by پارسا ورقائی, CC BY-SA 4.0, via Wikimedia Commons.