07th Expansion Wiki
This article is about a piece of terminology in
Higurashi When They Cry.

"Hinamizawa Syndrome" (雛見沢症候群 Hinamizawa Shōkōgun) is a term coined for the sudden mental issues arising in former residents of Hinamizawa after the Great Hinamizawa Disaster and the series of murders and stigmatization that followed.


Before World War II, Hinamizawa Syndrome was used to describe the homesickness developed in villagers who left the village, as they believed they could never leave for fear they would be cursed by their god Oyashiro-sama.

After the Great Hinamizawa Disaster, in which the entire population living in Hinamizawa was killed overnight by volcanic gas, there were a series of ritualistic murders and suicides being carried out by relatives of Hinamizawans. It was widely believed that the Disaster was Oyashiro-sama's wrath given form, and survivors were doing whatever they could to stave off his anger.

The manga-exclusive arc Onisarashi shows that many elderly people were especially devout, with Aki Kimiyoshi shown decorating her house with lots of charms and drowning puppies to pass on the negative karma her family would be receiving onto them. Other incidents of people killing their entire families before committing suicide themselves received widespread media coverage, and so people from Hinamizawa became stigmatized, not helped by rumors and legends of the villagers being descended from demons. People with similar surnames to the Three Families were even targeted and attacked by civilians, as they were said to be the most demonic out of all the villagers.

True Nature[]


This article or section contains untagged major spoilers for all of the original Higurashi When They Cry story and possibly the console-exclusive arcs. Readers who have not completed the story are advised not to proceed further.

Hinamizawa Syndrome is also the name given to a parasitic virus endemic to Hinamizawa and has persisted in the region for hundreds of years.

  1. True Origin
    1. Discovery and Research
  2. Characteristics
    1. Transmission
    2. Queen Carrier
    3. Medicinal Applications
  3. Trivia
  4. References

True Origin[]

Hinamizawa Syndrome is believed to have originated in the distant past when Hanyuu and her people came to Hinamizawa. Hinamizawa Syndrome's symptoms caused villagers to become violent from paranoia, giving rise to the idea that they were "demons." With the sacrifice of Hanyuu under the assumption she was a demon lord, the villagers calmed down in their paranoia and stopped suffering from Hinamizawa Syndrome, however the virus persisted in the region. The faith known as Oyashiro-sama was soon propagated by the villagers as a way of preventing symptoms from breaking out.

Discovery and Research[]

Over the years, Hinamizawa Syndrome became less effective than it originally was due to how strong the belief in Oyashiro-sama was, however that didn't mean carriers were completely immune to the virus.[1] Modern-day cases of Hinamizawa Syndrome arose in the 1940s, where several Japanese soldiers fighting in World War II that came from Hinamizawa were beginning to show erratic behavior. Hifumi Takano, an army physician, examined these soldiers and discovered the existence of the Hinamizawa Syndrome parasite. He believed this was a remarkable discovery, a parasite that could control human emotions, and sought funding to research Hinamizawa Syndrome for military applications but his request was denied; not only did the army not have the time and money to devote to research, they also thought he was insane. Dr. Takano later committed suicide, with his research notes inherited by his adoptive granddaughter Miyo Takano, who sought to continue his research.

The Self-Defense Force had actually refused research into Hinamizawa Syndrome when Dr. Takano was around due to strong evidence it was responsible for triggering the Marco Polo Bridge Incident, and the higher-ups believed it would cause problems with China if the true cause were revealed.[2] The SDF had renewed interest in the virus and wanted to fund research under their new weapons development project, the Alphabet Project. After gaining additional support from her old friend Koizumi, Takano received funding from the SDF and joined with Kyousuke Irie to open a clinic in Hinamizawa and begin research. The organization Tokyo later provided additional funding.



Research showed that the pathogen causing Hinamizawa Syndrome could only be found when the patient was alive, and even then only through lobotomization. Procuring live subjects was thus very important. The unique climate of Hinamizawa contributed to keeping the virus under control.[3]

The virus is transmitted through the air and through bodily fluids. It is very easy to get infected by the virus, however symptoms do no manifest unless one goes far away from Hinamizawa or becomes emotionally unstable.

Stages of Infection and Symptoms[]

There are five stages, or levels, of infection, however the first three Levels are inconsequential so long as the patient remains emotionally stable and lives a normal life.

Level 4 (L4) is considered critical condition. L4 patients will begin to notice Hanyuu, able to sense her presence and at times hear her.[4] Examples are shown in arcs like Minagoroshi when Tomitake is able to hear Hanyuu throwing a tantrum.

Level 5 (L5) is the terminal stage, which is difficult to return from without medicine or proper mental help. L5 patients will develop itchiness in their lymph nodes and so will begin scratching their necks. The syndrome affects the frontal lobes of the brain and induces doubt, making the patient develop a persecution complex and see hallucinations which usually manifest as formication, the sensation of maggots crawling in their skin. Patients will claw at their skin and throats to get rid of these imaginary bugs, which often results in them clawing their throats open and killing themselves through excessive blood loss. Even with the current medicine developed to combat the syndrome, it is unlikely for a terminal patient to recover below the L3 stage.[5]

Queen Carrier[]

Dr. Takano theorized the existence of a queen carrier parasite that inhabited firstborn women of the Furude family, connecting it with religious beliefs that shrine maidens had psychic powers and could calm people's souls. The existence of the queen was proven when it was discovered that patients getting near it would develop a substance in their brains that would calm them and reduce symptoms.[6] Not only that, the health of the queen carrier seemed to affect infected persons as well; Rika Furude, the current queen was being researched by the clinic and developed a fever for a few weeks, and the clinic had a highly increased number of visitors during that time. This correlation reinforced the idea that the queen carrier was important to the stabilization of Hinamizawa Syndrome.[7]

It was thus assumed that going too far from the vicinity of the queen carrier would cause patients to develop terminal symptoms.[8] If the queen carrier died or left the village, then it was likely that every single infected villager would jump to terminal stages within 48 hours. This was the conclusion reached after examining cases of entire communities going insane and committing suicide after the deaths of religious leaders, with incidents happening over the span of 48 hours.[7] There was no way to prove this theory true or false, and due to Hinamizawa's population encompassing over 2000 carriers, a contingency plan has been created for the worst-case scenario.

(The queen carrier theory is actually false as proven by Meakashi's credits. Although Rika was killed, many characters are shown to live well past 1983, meaning Emergency Manual 34 and the Great Hinamizawa Disaster have not happened.)

Medicinal Applications[]

The first successful vaccine to treat Hinamizawa Syndrome was C103, which suppresses the production of a certain hormone and thus prevents transmission of the syndrome. It was tested on Satoko Houjou and helped her go down to L3 levels,[9] though it had to be injected three times daily.[10] C117 was developed later, however its differences from previous developments are unclear due to it being a prototype.[11] The most recent vaccine C120 only requires two injections per day.[5] Using this medicine when one is not infected will result in fever, rashes, dilation and hallucinations.[12]

While researching the mechanisms behind how the syndrome controls a host's brain and induces derangement and paranoia, the H170 series of reagents was developed. H170 forces the brain into a state of agitation, and so when injected into a syndrome patient it makes the pathogen become unstable and makes them jump to L5. While it was created with the purpose of forcing certain reactions in patients to better test the exact mechanisms behind the syndrome pathogen, it also has a secondary military application as befitting the goal of the Alphabet Project.[10] Its most recent development is H173.


  • The numbers in H173 when written in romaji (hi-na-mi) form the first three syllables of Hinamizawa.


  1. Connecting Fragments 6: The second sacrifice
  2. Matsuribayashi Chapter 3
  3. Matsuribayashi Chapter 7
  4. Minagoroshi Day 5
  5. 5.0 5.1 Minagoroshi Day 2
  6. Connecting Fragments 4: Research is going well
  7. 7.0 7.1 Connecting Fragments 10: At a quarry in Yagouchi
  8. Connecting Fragments 12: Requesting assistance from a queen
  9. Connecting Fragments 14: An accident at the Shirakawa park
  10. 10.0 10.1 Connecting Fragments 2: H170
  11. Connecting Fragments 25: A roll of a one
  12. Minagoroshi Epilogue