Umibōzu – The Sea Monk

Translated and sourced from Mizuki Shigeru’s Mujara, Yokai Jiten, Japanese Wikipedia, and other sources

If you find yourself out sailing strange tides in an unfamiliar sea, the umibozu is not the kind of monk you should pray to for help.

The Legend of the Umibozu

Sailors in Japan’s yokai-haunted waters had many things to dread. Dark nights and stormy waters could bring funa yurei rising up from the depths demanding hishaku, a wooden ladel, that they would then use to fill a boat with water and sink it to the depths. But it was clear skies and calm waters that brought fear of the umibozu. Rising suddenly from the placid surface of the water, umibozu looked like a great ocean swell, a giant black head that would lurch upwards and upside ships, sending the sailors into murky waters. They were massive, rising as much as ten meters tall, and strong enough to snap a ship in two.

What is an Umibozu?

Umibozu (海坊主) translates literally as “sea monk.” They are known by other, similar names such as umi boshi (海法師) and umi nyudo (海入道), both of which are variations of the world “sea monk.” (“boshi “ and “nyudo” are other words for monk, meaning “teacher of the Buddhist laws” and “walker of the way” respectively). The name is entirely linked to appearance—the rounded head of an umibozu was said to resemble the shaved head of a Buddhist monk—and has no deeper connections to Buddhism. I have seen some English language sources saying that the umibozu are the spirits of drowned monks, but I haven’t found this claim supported by Japanese sources.

Traditionally, umibozu rise from calm waters. Their appearance is sometimes said to herald a coming storm, and they can be accompanied by other strange ocean phenomenon. Or even just feelings of dread. In any case, wise fishermen could read the signs that an umibozu was about, and would refuse to launch their boat until the waters were clear.

Accounts of umibozu differ wildly. They can be anything from a hairy creature resembling a sperm whale to a beautiful woman who can shape-change into a vicious monster. The classic umibozu is the one most often represented by ukiyo-e artists; that of a giant black head with two massive eyes thrusting up from the water. Umibozu can be gigantic, there have been reports of tiny umibozu, no more than a few feet or inches tall. Some say that these are children and that the massive umibozu are full grown adults. When they attack, some say that they cling to the hull of a ship to drag it down, or have great stretching arms that can pull a ship down by its mast. Some say that they try desperately to quench any lit fires on the boat. Some say they cry “Kuya kuya” as they attack, and that striking them with the oars will bring cries of pain, “Oitata!,” from the smaller species. In some legends, they can be repelled by tobacco smoke.

Most researchers think that umibozu are a misunderstanding of a natural occurrence. The shells of great ocean sea turtles or massive jellyfish rising suddenly from the water, or a black thunderhead of clouds rising in the distance have all been sited as the origin of umibozu legends.

A more recent candidate is a rare phenomenon called a rogue wave, which is a large and spontaneous ocean surface wave that occurs far out in the sea fitting almost exactly the traditional description of an umibozu. Rogue waves themselves were thought to be sailor’s folklore until the Draupner wave was recorded in 1995 off the coast of Norway.

Umi Bozu across Japan and Elsewhere

Unsurprisingly, as an island nation Japan has long had a deep and abiding fear of the ocean. An uncountable assortment of sea monsters live in the waters off of every coast. Each small fishing village created its own folklore, and as villages grew larger and merged into port cities mythologies mixed and blended, accounting for the massive and infinite variety.

Most Japanese yokai are regional. They were created in one particular area, and there they stayed. But the umibozu are widespread, and touch every part of Japan that is touched by the ocean. Because they are so widespread, over the centuries the story of umibozu has mixed with other sea creatures. In some accounts, the umibozu are like the funa yurei, demanding a spoon or a barrel in order to fill a boat with sea water. In some accounts, the umibozu are like the kappa, trying to suck the shirikodama from out of the human anus.

In the Tohoku region, before going out to sea for fishing the captain of fishing boats would give prayer to the Goddess of the Sea for safe passing. It is said that the umibozu are the retribution of the Goddess on any ship captain who fails to give her the proper respect.

In Okayama prefecture, the umibozu were considered to be an aspect of the yokai nurarihyon. Sailors in the Seto Inland Sea feared the rising of the nurarihyon’s large head from the water, which would flip ships over as a joke.

In Aomori prefecture, Shimokita district, Higashidori village, people who ate shark (eating shark was sometimes taboo in Japan, as sharks ate people so it was seen as cannibalistic) were said to become mojyabune (亡者船; ship of the dead), which was associated with the umibozu. People protected themselves from the mojyabune by mixing miso paste with water and pouring it into the ocean.

In Shizuoka prefecture, Kamo district, they told tales of the umi kozo, which refers to a young monk. The umi kozo was covered in a fine hair up to its eyes, and came up along people’s fishing lines, cackling hideously.

There have been stories of shape-changing umibozu as well. In Miyaki prefecture, on Ooshima island, they say that umibozu disguise themselves as a beautiful woman lost and swimming in the ocean. The same story is told in Iwate prefecture, where it is said that the woman will invite you to come into the water with her, and that anyone foolish enough to do so will be swallowed whole.

Many other countries have similar legends, or sea monsters that resemble the umibozu. In Mongolia there is the Mokuri Kokuri. In China the Kikokutan, and in Europe the Sea Monk and the Bishop fish haunt the oceans.

Reports of Umibozu

There have been several written accounts of umibozu. Many of these are eye-witness encounters appearing in newspapers or collected in the bound volumes that served as the popular literature of the time.

In the Kansei era (1789 – 1801), in a collection of writings called Kanso Jigo (閑窓自語), in Osaka prefecture, Kaitsuka city, there was a report of an umibozu that rose out of the water and stayed visible for three days before returning to the sea.

In Wakayama prefecture, in the 21rst year of Meiji (1888) the Miyako Shinbun newspaper reported an umibozu monster that was 2.4 meters long and weighed up to 263 kilograms. It was said to be light brown with orange eyes, with a mouth like a crocodile and a tail like a giant shrimp, with a voice like a cow.

In the collection Usō Kanwa (雨窓閑話), it was written that in Mie prefecture it was thought that the end of the month was the time for umibozu, and ships were prohibited from launching at that time. A sailor broke the ban and went to see at the end of the month. Sure enough, he soon encountered an umibozu who approached him and asked “Am I terrifying?” The sailor replied, “I find nothing as terrifying as trying to make my way in this world,” at which the umibozu suddenly vanished.

And the most recent account, published in the Mainichi Shinbun newspaper in 1971, told of a first-hand account by a ship that was tuna fishing near New Zealand. When they went to hoist up their catch, a giant animal came up tangled in the lines. The captain and crew panicked at what they were sure was some monster from the deep. The monster was brown colored, with deeply wrinkled skin, and eyes fifteen centimeters in diameter. They saw no nose or mouth. Only a part of the monster’s body came out of the water, with the rest hidden in the ocean water. The matter was investigated by Japan’s oceanography department, who felt that experienced fishermen were not likely to mistake a whale or a giant squid for something different. If, as the fishermen said, the visible part of the body that breached the surface was around 1.5 meters long, then the remainder of the body must be larger than any animal ever known.

Perhaps it was an umi bozu.

Translator’s Note:

This was posted by request for reader Stuart, who says he is writing a song about umi bozu.  Hope to hear that song when it is finished!  And also thanks to comic writer Brian Wood, in whose comic The Massive appearing in Dark Horse Presents I first heard about the Draupner wave and thought … that sounds like an umibozu!

Further Reading:

Read more yokai tales on

Funa Yurei

Nure Onago – The Soaked Woman

The Appearance of the Spirit Turtle


26 Comments (+add yours?)

  1. Mike
    Feb 21, 2012 @ 21:29:28

    That’s pretty cool! It’s interesting that Japanese sailors have their own mermaid myth too…I guess that lonely sailors at sea always see women among the waves….


  2. Zack Davisson
    Feb 21, 2012 @ 21:44:25

    Although I should add, Japan also has quite a rich mermaid mythology of its own, with a couple of different types. And a legend that if you eat mermaid flesh you gain immortality. But that is a post for a different day …


  3. Stuart
    Feb 22, 2012 @ 09:35:02

    Fantastic! Thanks a lot for your work! Particularly like the Usō Kanwa story. Lot’s of info there to start work on my composition! I’ll post it when it’s done (may be some time though…)


  4. Bill Ellis
    Feb 22, 2012 @ 10:58:52

    Interesting: there are Scottish/Scandinavian legends about rogue waves being the shapeshifted forms of witches or other boogies: if you use cold iron to cut the wave as it begins to break over the boat, you can kill the entity or the person who sent it. This belief seems still resonant behind the common belief that rogue waves come in groups of three, known as “The Three Sisters.”

    More to the point, your background seems to explain an interesting character in a lot of animation art sketches that I obtained, identified as coming from Episode 92 the recent CGI Gegege no Kitaro (2005-07).

    That’s him on the left and “Wave Boy” (or “Little Surfer Dude” as I like to call him) on the right. He’s portrayed as a huge fish, but carries the string of beads and shakujō of a stereotypical Buddhist monk. They combine forces, from what I can infer from the set of sketches, against a giant rogue wave, helped by Kitaro and his usual helpers.

    I always called him “The Fish Monk” (to distinguish him from the Fish Friar, who helps out at the local Catholic church’s lenten fundraisers) but perhaps this is Mizuki’s whimsical rendering of a umibozu or “Sea Monk”?


  5. Zack Davisson
    Feb 22, 2012 @ 11:21:43

    It isn’t suprising that a monster based on a natural phenomenom would exist all over the world. I have heard about the Three Sisters legend. I actually found that when I was looking up rogue waves for this article.

    And that “Wave Boy” in you picture is the yokai Iwana Bozu. Iwana is a type of fish, known as char in English, which is a species of trout.

    Here is an Iwana Bozu toy:


    • Bill Ellis
      Feb 22, 2012 @ 15:34:55

      Thank you for identifying my “Fish Monk.” “Wave Boy” (nami kozō) seems to be another yōkai though. From what I can determine, he’s another entity who agrees to become Iwana Bozu’s disciple. When I Googled for images, I did get the anime character, but also a photo of a monument to a real folklore entity of the same name located at Omaezaki-shi (Hamaoka sand dune):

      And a different one, this one at Maisaka Beach, Hamamatsu, Shizuoka Prefecture

      “Wave Boy” might make an interesting topic for a future blog as he seems to be a kind of patron yōkai for surfers of all kinds.


  6. Zack Davisson
    Feb 22, 2012 @ 15:57:16

    Oops! I mixed up “Wave Boy” and “Fish Monk!”

    Wave Boy there would be a good future post. I have a whole family of surfers who would like that.


  7. vilajunkie
    Feb 23, 2012 @ 21:40:22


    Your comment about Scottish sea legends reminded me of a spirit similar to the Usō Kanwa umibozu. The Blue Men (Scots Gaelic, “Na Fir Ghorma”) of the Minch are said to ask riddles and get in the last word if you speak to them; answer incorrectly and the ship gets sunk, give a clever answer or get in the last word and they disappear.

    Of course, these days a “blue man” in Irish and Scots Gaelic refers to people of African descent, since “black man” in Gaelic is a euphemism for the Devil.


    • Bill Ellis
      Feb 24, 2012 @ 13:45:07

      I found the story that includes cutting the three waves: it’s “The Ferryman,” in Katherine Briggs’s “A Dictionary of British Folk-Tales” (Indiana, 1971), Part B, V. 2, p. 649. It has the detail that I’d forgotten that the passenger assigned to cut the three waves was traveling to see his own mother. When he arrives at her cottage, he finds his mother and her two sisters (i.e., “The Three Sisters”) lying dead on the floor, each cut in half. “They were the witches who had troubled the ferry.” A note adds, “This story is usually told in Gaelic.”

      A cross reference leads to another story (Ibid., p. 612) current in the Shetlands, where a local fisherman makes a wager with a Finn (a ethnic group locally rumored to be witches because of their non-Indo-European language) that he would be able to catch at least one fish before Yule (the Winter Solstice). After much trouble with storms, he manages to catch an olik (Molva molva, or “ling,” a much prized big relative of the codfish). Immediately the boat is surrounded with angry waves, and it is nearly swamped, but the fisherman throws the cask of oil he carried to calm the water into the face of the largest and most dangerous wave.

      He manages to get back to harbor and soon after meets the Finn, whose teeth are broken and has a deep scar on his forehead. The Finn comments, “I’m paid dear eneuch fit dat olik. Doo didna only smore we mid dy oil but du solved me wi dy oli hjulk.” Briggs leaves the reader to work out the Shetland dialect, but with the help of an online dialect dictionary, I read this as “I sure paid dearly enough for that olik. You didn’t just smother us with that oil but you knocked me out with the oil jug.”

      These are all witch tales, however, rather that stories about a yōkai like the Umibōzu. For a parallel to that, probably kraken lore would be better. That creature was also said to rise unexpectedly from an otherwise calm ocean. The images do show a rounded head and huge eyes like the Japanese creature, though more stress is put on its octopus-like tentacles that supposedly could drag ships to the bottom.

      Wikipedia includes the following quote (from a 1781 Swedish work) that sounds very Umibōzu-like:

      “Gradually, Kraken ascends to the surface, and when he is at ten to twelve fathoms, the boats had better move out of his vicinity, as he will shortly thereafter burst up, like a floating island, spurting water from his dreadful nostrils and making ring waves around him, which can reach many miles. Could one doubt that this is the Leviathan of Job?”


      • vilajunkie
        Feb 25, 2012 @ 00:36:22

        Oh wow! Thanks for all the cool info. I have Briggs’ “Dictionary of Fairies” and access to “The Vanishing People”, but I’ve never been able to find copies of “A Dictionary of British Folk-Tales”, neither Part A nor Part B. Off topic, but, for being such an important, well-known British folklorist, why is so much of Briggs’ work hard to find and out of print?

        Back to the Umibozu: I thought of the Aspidichelone (sic) too, the giant fish mistaken for an island with a sweet-smelling breath from the Physiologus. AKA Zaratan, Jasconius (in “St Brendan’s Voyages”), Asp-Turtle, etc. But that’s getting away from the Umibozu legends and more into Namazu territory…

  8. cristyburne
    Feb 27, 2012 @ 05:21:17

    Brilliant post Zack…I have been telling kids they need a ladle to overcome umibozu for a while, but starting to lose confidence in my own advice! Great to see an expert like yourself backing up the idea. Of course each region has its own take on the legends, but I like to pick-and-choose the versions I tell. Artistic licence, perhaps?

    Thanks for the great post!!!


  9. Zack Davisson
    Feb 28, 2012 @ 22:47:50

    Thanks Crisy! I admit I have a hard time with the ladle connection with the umibozu … it is clearly borrowed from the funa yurei stories and seems wedged into umibozu stories.

    But that is folklore for you. It doesn’t fit into nice little packages with clear delineation like Pokemon cards. In some places in Japan, they tell the umibozu story mixed with the funa yurei story, and who am I to tell them they are wrong?


  10. daraintheclouds
    May 19, 2012 @ 08:55:49

    would you be able to provide links or directions to find the sources you used?


  11. Zack Davisson
    May 19, 2012 @ 11:49:55

    I list my sources right up at the top. I can’t really provide links because two of them are books that sit in my house! The other main source was Japanese wikipedia for Umi Bozu, which is in and of itself well sourced, so I consider my article to be using the same sources.

    Other than that, I found a few odds and ends elsewhere, mainly just checking other sources to see if they confirmed with what I read in my books and Wikipedia. And like I said, I first heard about the Draupner wave in Brian Wood’s comic.


  12. Theonlytrue
    Nov 13, 2015 @ 04:53:43

    is still ‘exist’ ? i wonder if they still exist till now . can human see them ?


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  14. skandallum
    Jun 12, 2016 @ 06:22:01

    Great post, many thanks for it!

    Btw, I checked this Chinese ‘kikokutan’, as it sounds strange in Mandarin, and in Baidu I found that guǐkūtān (鬼哭滩) is actually not refers to the creature, but to the beach (literally ‘ghost cry beach’) near to Hainan Island, where used to know as a place better to avaiod for sailors as hunted by Umibōzus and similar yokais.


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