or refers to a traditional Japanese method of cursing a target, so called because it is conducted during the hours of the Ox (between 1 and 3 AM). The practitioner—typically a scorned woman—hammers nails into the of a Shinto shrine while dressed in white and crowned with an iron ring laden by three upright candles. In the common modern-day depiction, the nails are driven through a straw effigy of the victim, impaling the doll upon the tree. The ritual must be repeated seven days in a row, after which the curse is believed to succeed, causing death to the target. However, being witnessed in the act is thought to nullify the spell. The Kifune Shrine in Kyoto is famously associated with this ritual.
Also variously called , , or .
Common methods of portraying this ritual developed during the Edo period (1603âÂÂ1868 CE).
The woman performing the curse is generally depicted as dressed in white, with disheveled hair, wearing an iron "crown" that holds three burning candles. She hangs a mirror around her neck (which is hidden in her clothing) and wears a pair of tall clogs (geta). She nails a straw doll representing her target to a at the Shinto shrine.
The iron "crown" that she wears is actually a or trivet, a stand for setting cookware above a heat source, which she wears inverted, slipping the iron ring over her head and sticking candles on its three legs.
It was believed that the spot struck on the straw doll would correspond to the area of the body where the target would soon experience illness or injury. However, this straw doll or other form of effigy was not always depicted in the ritual even relatively late in the Edo Period. For instance, Toriyama Sekien's Konjaku Gazu Zoku Hyakki (1779, pictured top right) shows the woman holding a hammer but no doll, nor is the doll mentioned in the caption. In that illustration, the nails are driven directly into the branches of the sacred tree.
The props are described somewhat differently, depending on the source. Nails of a particular size called are required according to some authorities. The practitioner may hold a comb in her mouth or a "torch of bamboo and pine roots lighted at both ends." The "proper witching hour" is, strictly speaking, the ushi no mitsu doki (2:00âÂÂ2:30 am).
In Sekien's or Hokusai's print (above), the woman performing the curse ritual is depicted with a black ox by her side. Such a creature is expected to appear on the seventh night of the ritual, and one must stride over or straddle the animal to complete the curse, but if a practitioner betrays their fear of the ox, the "potency of the charm is lost."
The term <onlyinclude> once only referred to worshipping at a shrine during the hours of the ox, and the curse connotation developed later. At the Kifune Shrine in Kyoto, it was said that if one prayed here at the "ox hour of the ox day of the ox month of the ox year" their wish was likely to be granted, because it was during this exact moment that the Kifune deity was believed to descend upon the shrine. However, this shrine became known a cursing spot later on.
The Kifune Shrine became strongly associated with the ox hour curse due in part to the popular medieval legend of the Hashihime of Uji ("The Princess of the "). This legend is considered the origin of the Ushi no toki mairi curse ritual. According to the story, the mortal woman Hashihime was the daughter of a certain nobleman, but consumed by jealousy, made a wish to become a kijin (an oni demon) capable of destroying her romantic rival. After seven days at Kifune Shrine, she was finally given a revelation by the resident deity "to bathe for thirty-seven days in the rapids of the Uji River." Although Kifune has later been described as the proper site for the ritual, Hashihime only learned the technique there, and enacted it miles away (Kifune is in northern Kyoto, and the Uji River is to the south).
The earliest written text of the legend appears in a late Kamakura-period variant text (Yashirobon codex) of The Tale of Heike, in the Tsurugi no maki ("Book of the Sword") chapter. The tale claims that Hashihime was originally a mortal during the reign of Emperor Saga (809 to 823 CE), but after turning into a demon, killing her rival and her lover's kinsmen, then indiscriminately slaying other innocent parties, she lived long beyond a normal human life span. She eventually would attack the samurai Watanabe no Tsuna at the only to have her arm severed by the sword . The samurai kept the demon's arm, whose power was contained by the Abe no Seimei, via chanting the Ninnà Â-kyà  sutra. In this variant of the tale, the ceremony that Hashihime performs at the Uji River to transform into a demon is described as follows:
<blockquote> Secluding herself in a deserted spot, she divided her long hair into five bunches and fashioned these bunches into horns. She daubed her face with vermilion and her body with cinnabar, set on her head an iron tripod with burning brands [* ] attached to its legs and held in her mouth another brand, burning at both ends.
</blockquote>
Here, the author describes Hashihime wearing the tripod (here called ) and holding lit torches (similar to candles in later traditions), but her paints her entire face and body red, rather than remaining in pure white clothing.
Later, during the Muromachi period, this legend was adapted by Zeami into the Noh play Kanawa or "The Iron Crown." The Noh play inherits essentially the same outfit for Hashihime, who is commanded by an oracle to "daub [her] face with red and wear scarlet clothing." The play uses neither a straw doll nor hammer, but has the Yinyang master Seimei create "two life-size straw effigies of the man and his new wife [with] their names [placed] inside" in order to perform the rites to exorcize Hashihime's demon. It is likely that the later form of the ushi no mairi developed afterwards, </onlyinclude>
The use of dolls in cursing rituals has been practiced since antiquity, with a reference in the Nihon Shoki chronicle under the reign of Emperor YÃ Âmei, which describes that in 587 CE Nakatomi no Katsumi no Muraji "prepared figures of the ... and [spellcast] them," but the spell did not work. However, this record does not say if the dolls were poked by sharp implements.
Archeological remains of humanoid dolls have been suspected of being used for curses. These often have realistically drawn ink faces, and others have iron nails driven into their torsos. One such doll from the 8th century is held by the Nara National Research Institute for Cultural Properties. Another effigy, from the Tatechà  site in Matsue, Shimane, depicts a female figure dressed as a noblewoman, with three wooden nails driven into it, aimed at her breasts and heart.
In Japanese law studies, attempts to commit murder through the ushi no mairi is often cited as the "textbook example of impossibility defense case crime."