Hitotsumono is a Buddhism or Shinto ritual/event held in festivals or gatherings in shrines and temples. A person or a doll dressed in a chigo (a boy acolyte) costume called Hitotsumono participates in a divine procession or performs a rite. Hitotsumono is written as "一つ物" or "一ツ物" in common, and also as "一物"or "一者" in the historical materials. Not having a performance and dance, Hitotsumono includes few, so to speak, elements of performing art. In the Japanese folklore, there is an established theory that Hitotsumono is a yorishiro (a spiritualistic medium), or a relic of a yorishiro while there is a different theory that Hitotsumono originates in furyu (divine dance).
According to the historical documents and pictures, "Umaosa" dressed in a similar costume was sometimes described as Hitotsumono. Therefore, it is considered that the origin of Hitotsumono is Umaosa. Umaosa was furyu, a divine dance performed by a child who rode on a horse dedicated by the Imperial Court, that was held in goryoe (a spirit-pacifying ceremony) of the Yasaka-jinja Shrine. In the late Heian period, Hitotsumono first appeared in the historical documents, for example, in the description of the Ujigami-jinja Shrine in the "Cyuyuki" (a diary of a court official). Hitotsumono has been frequently held along with other performances such as denraku (ritual dance and music), yabusame (horseback archery), horse racing, sumo, the king dance and shishimai (lion dance). In the late Heian period, like the king dance, as one of such a series of performance arts, Hitotsumono was established in the festivals or Buddhism gatherings in the countries near Kyoto, and in the Medieval Period, it spread to various regions.
Hitotsumono is generally characterized by a child performing a role, riding a horse (in some rituals, setting his foot on the ground was taboo), wearing a hat decorated with tail feathers of a mountain bird or paper strips, and being made up. The above characteristics were considered to be the influence of a belief that worships young children, for example, not setting his foot on the ground signified his divinity, and the decoration and make-up were the implements for a yorishiro (a spiritualistic medium). Also, occupying a significant position in the divine procession, and not performing arts, Hitotsunomono was interpreted as a yorishiro. Hitotsumono is considered to mean "one thing" or "fewness" from the above interpretation.
On the other hand, there is a different interpretation that Hitotsumono was not a yorishiro because the characteristics described previously didn't have special religious meanings; a horseback riding in a divine procession was not unique, and furyu also had decoration and make-up. According to this interpretation, it is thought Hitotsumono meant "the most prominent thing" and furyu, once in fashion, was called Hitotsumono. In this explanation, Umaosa, which was a popular furyu, was initially called Hitostumono and furyu itself came to be called Hitotsumono, which was latterly recognized as yorishiro due to the transformation of folklore in various regions.
In some regions, there is the festival of Hitotsumono, or possibly Hitotsumono. A person becomes Hitotsumono in shrines such as Kasuga Wakamiya On-Matsuri festival (Nara City), Agata-jinja Shrine (Uji City), Kogawa-dera Temple (Kogawa town), Sone-tenmangu Shrine, Arai-jinja Shrine, Takasago-jinja Shrine (Takasago City), Itate hyozu-jinja Shrine, Oshio tenmangu Shrine (Himeji City), Kotohiki-hachimangu Shrine (Kannonji City), Kumaoka-hachimangu Shrine and Uga-jinja Shrine (Mitoyo City). In Kumano hayatama-taisha Shrine (Shingu City), Daihou-hachimangu Shrine (Shimozuma City) and Hachioji-sya Shrine (Konan City), a doll becomes Hitotumono. In Daihou-hachimangu Shrine, the event of mushiokuri (torch procession), which drives impurity away, and the influence of hitomigoku (a human sacrifice) are seen in the festival.