The Kiraigou (帰来迎, known as Ceremony of Passage in the fanmade translation) is a ritual in Fatal Frame IV: Mask of the Lunar Eclipse, performed during a lunar eclipse once every decade. It is a very important tradition on the Rougetsu Island because it will stop the Blooming (the final stage of the sickness called Luna Sedata Syndrome). It is also said to open a pathway via moonlight to allow the previously deceased to travel into the underworld and be at peace.
The ceremony consists of six females: the Utsuwa "Vessel" (who funnels the dead onto the moon path to the underworld) and the Kanade "Accompanists" (whom play the Lunar Melody which summon, soothe, and guide the dead). Originally these participants were chosen by the Tsukimori Maidens, however the Tsukimori family and their traditions died out. Dr. Shigeto Haibara, the current owner of the Haibara Hospital, wanted to observe a forbidden form of the Kagura Dance called the "Kiraigou" (Ceremony of Passage) in which the Utsuwa wears the Mask of the Lunar Eclipse during the dance. This form of the dance had centuries ago caused a great disaster on the island called "The Day Without Suffering" (which occurred when the Ceremony of Passage and the Kagura Dance failed) and was therefore forbidden, yet Doctor Haibara wanted to recreate it in the hopes of better understanding the effects of the ceremony on Luna Sedata Syndrome.
Haibara chose Sakuya Haibara (his daughter who was suffering from the final stages of the Luna Sedata Syndrome) to be the Utsuwa, then had his son, You Haibara to kidnap Ruka Minazuki, Misaki Asō, Madoka Tsukimori, Marie Shinomiya, Tomoe Nanamura (suffering from early stages of the syndrome) to be the Kanade, and made himself the ceremony master. Doctor Haibara also commissioned Ruka's father to recreate the Mask of the Lunar Eclipse.
On September 17, one Kagura Dance Ritual was performed on Rougetsu Island for tourists in an outdoor ceremonial field , while at the same time Doctor Haibara secretly had his chosen dancers perform the similar Kiraigou (Ceremony of Passage) ritual in the traditional underground location. Yet, both ceremonies failed. Performing both dances at the same time met with dire results as the surface Kagura dance Utsuwa and Kanade died, while the Kiraigou dancers below met with strange fates. Sakuya momentarily bloomed then fell into a coma-like state and her Kanade dancers lost the memories of their childhood.
Doctor Haibara, fearing that his ritual would be discovered, locked away his daughter in a secret holding cell in the hospital's basement for further observation and study. He then had You Haibara lock the five girls used as the Kanade in a moon purification chamber beneath Haibara Hospital where they were later discovered and rescued by Choushiro Kirishima. Afterwards, You Haibara went into hiding and disappeared taking the heat off of his father and nearly masking the Doctor's involvement in the failed, forbidden ritual.
Two years later, on the anniversary of the failed Kagura, Sakuya awoke from her coma in full bloom and spread another "Day Without Suffering" disaster that killed off all of the people that remained on Rougetsu island, including Doctor Shigeto Haibara. Everyone who looked upon, or saw, her face bloomed instantly and then died. Sakuya continued to roam the island causing everyone still living to bloom and then turn into ghosts until years later when, during the next lunar eclipse, Ruka successfully performed the Kiraigou Ritual reversing Sakuya's blooming and funneled all the dead souls she created into the underworld.