Ghost stories surrounding lakes and reservoirs across Japan are a blend of ancient legends, specific structures, actual local information, and unexplained personal accounts. In this article, we separated and examined external rumor-sharing pages and local government/official tourism materials for each location, comparing how much of the claims in the rumors can be verified by independent sources. The ranking is based solely on the quality of the materials, not on the truthfulness or danger of the supernatural occurrences.
Survey methods and evaluation criteria
We categorized the dates, uses, structures, traditions, and phenomena actually written on the rumor pages into individual claims and compared them with local government or official tourism materials. The results were classified into five categories: "Agreement," where all claims are supported; "Partial Agreement," where there is a mix of support and unconfirmed information; "Disagreement," where there is insufficient comparative data; and "Unmeasurable," where important information not found in the rumors was discovered, although a direct comparison is not possible. We did not count the matching of locations or the mere inclusion of rumors as evidence of a supernatural phenomenon, nor did we consider the absence of information as negative evidence.
| Rank | point | The main points of the rumor | judgement | Document quality |
|---|---|---|---|---|
| 1 | Ojagaike Pond (Togane City, Chiba Prefecture) | The local history page describes Ojagaike Pond (Togane City, Chiba Prefecture) as "an irrigation reservoir completed in 1614 (Keicho 19)" and states that "its circumference is approximately 4.5 km." | Partial match | 89/100 |
| 2 | Kawachi Reservoir (Yahatahigashi Ward, Kitakyushu City, Fukuoka Prefecture) | The page listing haunted spots features Minamikawachi Bridge, located south of Kawachi Reservoir (Yahatahigashi Ward, Kitakyushu City, Fukuoka Prefecture), and describes a female ghost appearing at Minamikawachi Bridge late at night, as well as mentioning that "a female ghost stands at Minamikawachi Bridge in the middle of the night," and that "when crossing this bridge..." | New facts | 86/100 |
| 3 | Lake Aoki (Omachi City, Nagano Prefecture) | The page featuring paranormal observations describes Lake Aoki (Omachi City, Nagano Prefecture) as "the largest of the three Nishina Lakes and shaped like a heart." It then goes on to describe the lakeside as being "filled with the gaze of many people..." | Partial match | 83/100 |
1st Place: Ojagaike Pond (Togane City, Chiba Prefecture) | Partial Match (89 points)
The rumored details
The page introducing local legends describes Ojagaike Pond (Togane City, Chiba Prefecture) as "an irrigation reservoir completed in 1614" and "with a circumference of approximately 4.5 km." It further introduces legends about a snake god and a daughter, including the saying that "if you walk around the pond seven and a half times, a giant snake will appear on the surface of the water," and a story that on rainy nights, the sound of weaving can be heard from the bottom of the pond.
Source of the rumor and date of verification
I confirmed the rumor on a separate page in the "Comprehensive Compendium of Japanese Folklore." This page is a secondary publication that compiles multiple legends, and the original source or date of origin for each legend cannot be determined from the page text. Therefore, the publication status of the legend and the actual events will be treated separately.
- "Ojagaike" (Male Snake Pond) from the Great Compendium of Japanese Folklore(Confirmed on 2026-09-20) — Ojagaike Pond is an irrigation reservoir completed in 1614 (Keicho 19). It took 10 years to build and is a fairly large reservoir with a circumference of approximately 4.5 km.
Things that could be confirmed from official and primary source materials
The Chiba Prefecture official tourism website describes Ojagaike Pond (Togane City, Chiba Prefecture) as a large reservoir whose construction was started in 1604 by the local magistrate, Shimada Iehaku. It covers an area of approximately 25 hectares with a circumference of about 4.5 km, and it was confirmed that it was a facility to save villages from drought, and that it is currently used for hiking, fishing, and sightseeing. However, there is no explanation on the official page regarding its completion in 1614, the appearance of a giant snake, or the sound of weaving.
- Chiba Prefecture Official Tourism Website "Ojagaike Pond"(Confirmed on 2026-09-20) — A large reservoir whose construction was started in 1604 during the early Edo period by the then-local magistrate, Shimada Ihaku. It has a circumference of approximately 4.5 km and an area of approximately 25 hectares.
Points of agreement/contradictions
The fact that the pond is an artificial reservoir and its size, with a circumference of approximately 4.5 km, is consistent between the rumors page and the official tourist information. However, the 1614 completion date mentioned in the rumors cannot be confirmed solely by the 1604 start date stated on the official page. Furthermore, no records were found to support the legends of the giant snake or the sound of weaving as actual phenomena. Therefore, only the physical background is supported, and the legends remain unconfirmed.
| The rumored atomic claim | Matching results | reason | Corresponding documents |
|---|---|---|---|
| An irrigation reservoir completed in 1614 (Keicho 19). | Unconfirmed | Official tourist information indicates that construction began in 1604 and that it was used as a reservoir, but the text does not confirm its completion in 1614. | No official data available for direct comparison. |
| The circumference is approximately 4.5 km. | support | The Chiba Prefecture official tourism website clearly states that the area around Ojagaike Pond is approximately 4.5 km, supporting the same subject and figure. | Chiba Prefecture Official Tourism Website "Ojagaike Pond" |
| After walking around the pond seven and a half times, a giant snake will appear on the surface of the water. | Unconfirmed | There are no independent official records among the materials obtained that can support or refute this legend as a phenomenon. | No official data available for direct comparison. |
Alternative interpretation
The intricate lakeshore, long history of land reclamation, place names including snakes, and water deity worship may have intertwined multiple narratives. While the sounds of water at night and surrounding daily life may also sound like weaving, it is not possible to determine individual origins or sound sources based solely on the materials provided.
Scope and limitations of the investigation
The scope of verification is limited to the legend introduction pages and the information on the Chiba Prefecture official tourism website that could be obtained directly. We have not checked the original historical sources for each legend, primary records supporting the 1614 completion date, nighttime acoustic surveys, or original eyewitness accounts. The absence of any mention of supernatural occurrences on the official page is not treated as refuting evidence.
Verification results: Partial match
The fact that it is an artificial reservoir and the specific claim of a circumference of approximately 4.5 km were supported by independent official documents. On the other hand, the year of completion (1614), the appearance of a giant snake, and the sound of weaving cannot be definitively compared with the official documents in question. The supported aspects are limited to the physical background of the pond and do not indicate the occurrence of any supernatural phenomena, so it is only a "partial agreement."
Document Quality Score
| Source transparency | 30/30 | We can directly access the rumor page and the Chiba Prefecture official tourism website using separate URLs, and show how each claim is addressed. |
|---|---|---|
| Historical and spatial context | 24/25 | You can find specific details from official documents, including the year construction began, the purpose of the development, the surrounding area and size, and the current use. |
| Safety information | 18/20 | The official website contains address, transportation, and parking information, allowing you to plan your basic safety precautions for your visit. |
| Newness of information | 8/15 | While the verification date is consistent, the official page does not display individual last update dates, which limits the ability to assess freshness. |
| Transparency of the source of rumors | 9/10 | While multiple texts of the tradition can be directly viewed, the original source of each tradition is not indicated. |
| total | 89/100 | This is the overall quality of the materials. It does not represent the degree of truthfulness or danger associated with the supernatural phenomena. |
Safety information and maps
Be careful of falls and slips near water and on unpaved areas, and avoid walking alone at night. Follow local signs when parking or walking, and do not enter private property or restricted areas.
Map location: This is the coordinate of the center of the water area of Ojagaike Pond, confirmed using publicly available geographic data.
Check the area around Ojagaike Pond (Togane City, Chiba Prefecture) on Google Maps.
2nd Place: Kawachi Reservoir (Yahatahigashi Ward, Kitakyushu City, Fukuoka Prefecture) | New Facts (86 points)
The rumored details
The page listing haunted spots features Minamikawachi Bridge, located south of Kawachi Reservoir (Yahatahigashi Ward, Kitakyushu City, Fukuoka Prefecture), and claims that "a female ghost stands at Minamikawachi Bridge late at night" and "dragging anyone who crosses the bridge into the pond." Another rumor is also included about hearing voices at a small, abandoned building that supposedly existed there in the past.
Source of the rumor and date of verification
The rumor was confirmed on the individual page for "Awe." The page specifically identifies Minamikawachi Bridge and Kawachi Reservoir as the locations, but it does not specify the first appearance of the female ghost or the alleged pull-in, the witnesses, the date of recording, or the verification procedure. It will be treated as a secondary publication with an unknown first appearance.
- Awe-inspiring "Kawachi Reservoir"(Confirmed on 2026-09-20) — It is said that at Minamikawachi Bridge, located to the south of this area, the ghost of a woman who committed suicide by jumping off the bridge stands there in the middle of the night and appears beneath the bridge. It is also said that she drags anyone who crosses the bridge into the pond.
Things that could be confirmed from official and primary source materials
Regarding Kawachi Reservoir (Yahatahigashi Ward, Kitakyushu City, Fukuoka Prefecture), Kitakyushu City explains that it is an artificial lake created by Nippon Steel Corporation located upstream of the Itabitsu River. The Minamikawachi Bridge, which spans Kawachi Reservoir (Yahatahigashi Ward, Kitakyushu City, Fukuoka Prefecture), was designated a National Important Cultural Property on December 19, 2006, and is the only lingual truss steel bridge still existing in Japan. The official website provides information on seasonal scenery and surrounding facilities, but it does not mention the female ghost or the phenomenon of people being pulled into the water.
- Kitakyushu City: "Welcome to Kawachi Reservoir"(Confirmed on 2026-09-20) — The Minami-Kawachi Bridge, which spans the Kawachi Reservoir, was designated a National Important Cultural Property (structure) on December 19, 2006. It is the only surviving steel bridge in Japan built using an architectural style called a lenticular truss, and its value in the history of bridge technology was highly evaluated.
Points of agreement/contradictions
The rumors and official documents share the same subject matter: the Kawachi Reservoir and the Minami-Kawachi Bridge. However, the mere existence and location of the bridge do not support the supernatural occurrences. There are no official records that allow for a direct comparison between the female ghost and the alleged pull-in, so neither support nor contradiction is established. On the other hand, the official documents confirmed important historical details not found on the rumor page, such as the bridge's structural form and its designation as a cultural property.
| The rumored atomic claim | Matching results | reason | Corresponding documents |
|---|---|---|---|
| A female ghost is said to stand at Minamikawachi Bridge late at night. | Unconfirmed | There are no independent public records in the Kitakyushu City documents obtained this time that support or deny the appearance of a female spirit. | No official data available for direct comparison. |
| This bridge drags anyone who crosses it into the pond. | Unconfirmed | There are no official documents or verification records that allow for a direct comparison of the phenomenon of passersby being pulled into the pond by an invisible force. | No official data available for direct comparison. |
Alternative interpretation
On a bridge at night, reflections on the water's surface, shadows of trees and bridge materials, sounds of wind and water, and narrowed visibility may be perceived as human figures or voices. However, since there are no original records detailing the specific conditions of each experience, it is not possible to definitively attribute these to specific natural phenomena or psychological factors.
Scope and limitations of the investigation
The information obtained directly comes from rumor pages and Kitakyushu City's information pages. We have not checked the initial appearance of the rumors, individual testimonies, police and fire records, or nighttime observation data around the bridge. The fact that the strange occurrences are not listed on the official page is not a counter-evidence; this judgment is based on the lack of comparable records and the newly confirmed history of the bridge, which will be presented separately.
Verification results: New facts
The two claims—that a female ghost and a body pull—could neither be supported nor refuted in the official documents presented. On the other hand, the fact that Minamikawachi Bridge, the central setting of the rumors, is the only existing lenticular truss steel bridge in Japan designated as a National Important Cultural Property, is a specific structural and historical detail not mentioned on the rumor page. While this does not prove the supernatural occurrence, we have included it as a "new fact" to change our understanding of the location.
Document Quality Score
| Source transparency | 30/30 | You can directly access the individual pages for the rumors and the individual guide pages for Kitakyushu City, separating the setting from the claims. |
|---|---|---|
| Historical and spatial context | 25/25 | You can find specific details in official documents, including the entity managing the artificial lake, the date the bridge was designated, its structural type, and its cultural heritage value. |
| Safety information | 17/20 | You can check information about surrounding facilities and traffic conditions from Kitakyushu City's guide, but you will need to check separately for detailed restrictions around waterfront areas. |
| Newness of information | 7/15 | The Kitakyushu City page was last updated on October 31, 2025, but the rumor page was last updated in 2023, so there is a difference. |
| Transparency of the source of rumors | 7/10 | While the details and location of the supernatural occurrences are clearly stated, there is a lack of information regarding their initial appearance, witnesses, and the date and time of occurrence. |
| total | 86/100 | This is the overall quality of the materials. It does not represent the degree of truthfulness or danger associated with the supernatural phenomena. |
Safety information and maps
Prioritize preventing falls when using bridges or waterfronts, and avoid nighttime dares and loitering on roadways. Check the latest information on construction and traffic restrictions from Kitakyushu City's guides, and do not cross fences or "no entry" signs.
Map location: This is the coordinate of the center of the Kawachi Reservoir water area, confirmed using publicly available geographic data.
3rd Place: Lake Aoki (Omachi City, Nagano Prefecture) | Partial Match (83 points)
The rumored details
The page featuring paranormal observations describes Lake Aoki (Omachi City, Nagano Prefecture) as "the largest of the three Nishina Lakes and shaped like a heart." It then mentions rumors of "feeling the presence or gaze of many people" and "the appearance of fireballs" around the lake, and includes an account of someone seeing multiple small lights on the lake's surface out of season.
Source of the rumor and date of verification
I confirmed the rumor in the paranormal investigation section "Aoki Lake | Rumored Ghost Stories." The page summarizes the lake's characteristics and the contributor's experience, but it does not specify any third-party observation records regarding the presence or fireballs, the date and time of occurrence, weather conditions, or original source. I will treat this as a secondary, republished experience.
- Paranormal Investigation: "Aoki Lake | Rumored Ghost Stories"(Confirmed on 2026-09-20) — The paranormal phenomena at Lake Aoki include feeling the presence of many people and the appearance of fireballs. Strange occurrences have been reported where people feel the presence of many people even though no one is actually there.
Things that could be confirmed from official and primary source materials
The official tourism website for Omachi City, Nagano Prefecture, describes Lake Aoki (Omachi City) as the largest of the three Nishina Lakes, with its beautiful heart-shaped waters. It also provides information on seasonal changes such as the cherry blossoms in spring, the deep green of summer, the autumn leaves, and the migratory birds in winter, as well as cycling along the lakeside road, early morning SUP in summer, and nighttime firefly cruises. There is no mention of gazes, presences, or fireballs on the official page.
- Omachi City Official Tourism Website "Aoki Lake"(Confirmed on 2026-09-20) — Lake Aoki is the largest of the three Nishina Lakes and boasts beautiful heart-shaped waters. It displays a rich variety of scenery throughout the seasons, with cherry blossoms in spring, lush greenery in summer, vibrant autumn leaves, and migratory birds arriving in winter.
Points of agreement/contradictions
The physical description of it being the largest of the three Nishina Lakes and its heart shape is consistent between the rumor page and the official tourist information. On the other hand, the presence of a large crowd and the fireball cannot be supported or refuted by the official information. The official page promotes a nighttime firefly cruise, so there is an environmental possibility that lights could be seen near the lake surface, but it cannot be definitively said that this is the same phenomenon as the individual experience described on the rumor page.
| The rumored atomic claim | Matching results | reason | Corresponding documents |
|---|---|---|---|
| It is the largest of the three Nishina Lakes and is heart-shaped. | support | The official tourism website for Omachi City clearly states that it is the largest of the three Nishina Lakes and is heart-shaped, highlighting the same characteristics. | Omachi City Official Tourism Website "Aoki Lake" |
| I can sense the gaze and presence of many people. | Unconfirmed | There are no observational records in the official documents obtained this time that objectively support or refute the claims of gaze or presence. | No official data available for direct comparison. |
| A fireball appears. | Unconfirmed | There is no information available regarding the date and time of the fireball's occurrence, images, third-party records, or weather data, and it cannot be directly compared with official tourism information. | No official data available for direct comparison. |
Alternative interpretation
The small lights on the lake's surface could be caused by several things, including distant lights, moving boats or vehicles, reflections, or insects. The official tourism page also advertises a nighttime firefly cruise, but the rumored experience is said to have been out of season, and since there are no dates, times, or videos, we cannot directly apply that description.
Scope and limitations of the investigation
The sources I consulted were a rumor page and the official Omachi City tourism website. I was unable to obtain the exact date and time of the experience, observation location, weather, location of the light source, or records of any companions. Official tourism materials are intended for nature and sightseeing information, so the mere absence of mention of the strange occurrence does not necessarily mean that the phenomenon was denied.
Verification results: Partial match
Official tourism materials supported the specific geographical claims that Lake Aoki is the largest of the three Nishina Lakes and is heart-shaped. However, there are no independent records to directly compare the presence of many people and the fireball, and these remain unconfirmed. Since only the physical characteristics of the lake were supported and not to corroborate the supernatural occurrences, it was classified as a "partial match."
Document Quality Score
| Source transparency | 28/30 | You can directly access separate pages for rumors and official tourism information, allowing you to compare the lake's characteristics with the claims of strange occurrences. |
|---|---|---|
| Historical and spatial context | 21/25 | While the location, shape, seasonal scenery, and lakeside use of the Nishina Three Lakes can be confirmed, primary sources regarding its formation history have not yet been obtained. |
| Safety information | 17/20 | While the official tourism page provides an overview of lakeside use, you will need to check the water safety regulations for different weather conditions separately. |
| Newness of information | 8/15 | Although both pages were obtained on the same day, the date and time of the rumored experience could not be determined, making it impossible to assess the freshness of the phenomenon information. |
| Transparency of the source of rumors | 9/10 | While specific phenomena and personal accounts are available, the date and time of observation, records of accompanying persons, and traceability to the original sources are lacking. |
| total | 83/100 | This is the overall quality of the materials. It does not represent the degree of truthfulness or danger associated with the supernatural phenomena. |
Safety information and maps
On lakeside roads, be careful of vehicles and bicycles, and follow the rules of the management company and weather conditions when engaging in water activities. Do not approach the water's edge at night by following lights, and do not enter restricted areas or private property.
Map location: This is the coordinate of the center of Lake Aoki's water area, confirmed using publicly available geographic data.
Check the area around Lake Aoki (Omachi City, Nagano Prefecture) on Google Maps.
What I learned by crossing locations
While the bodies of water at all three locations could be identified through official documents, the scope of comparison differed. At Ojagaike Pond, the size of the pond and at Aoki Lake, the shape of the lake and its position within the Nishina Three Lakes coincided with independent documents. On the other hand, no official records indicating the appearance or cause of the strange occurrences could be found. At Kawachi Reservoir, although a direct comparison of the strange occurrences was not possible, it was discovered that the Minami-Kawachi Bridge, the setting of the rumors, is a nationally important cultural property with the only existing structural form in Japan, providing a new perspective on the location.
summary
The documents we were able to verify through cross-referencing were specific facts such as the establishment, size, shape, and use of the waterfront, as well as the cultural heritage value of the bridge. Regarding the giant snake, the female spirit, being pulled in, the gaze, and the fireball, we were unable to support or refute them based on the official documents we obtained. Therefore, instead of treating the rumors as fact, it is necessary to distinguish between the confirmed physical background and the unconfirmed narratives. When you are at the site, do not enter private property or restricted areas, and prioritize guidance from the administrator during daylight hours.
FAQ
Can we conclude that a supernatural phenomenon is real simply because there is a page about it?
No. The rumor page is a resource for checking what stories are being published. The existence of a phenomenon is only evaluated separately if independent official records and verifiable materials support the same claim.
Does "partial match" mean that some of the paranormal phenomena have been proven?
That's not the case. This partial agreement only supports the physical and geographical claims included in the rumors, such as the size of the pond and the shape of the lake, while the claims about the supernatural phenomenon remain unconfirmed.
What precautions should I take when visiting the area?
Avoid traveling alone at night, entering restricted areas, parking on the street, and approaching the waterfront carelessly. It is necessary to check the latest information from administrators and local authorities, as well as weather conditions and traffic restrictions, in advance.
How to read this article and safety precautions
" [2026 Latest] Top 3 Ranking of Paranormal Rumors about Lakes, Ponds, and Swamps Nationwide This is an article compiled by the Horror Tales File editorial team as a story, based on publicly available information, rumors circulating in the community, and information submitted by readers. It does not definitively state the authenticity of paranormal phenomena.
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