In the 16th volume, first half of the Miscellaneous Morsels from Youyang of the Tang dynasty, volume 462 of the Taiping Guangji of Northern Song dynasty, the "night-going leisure woman" is a nocturnal strange bird that steals people's babies and about it is written, "perhaps it is the changed form of what was once someone who died in childbirth" (或言産死者所化).
The ubume's blood-soaked appearance is thought to be because in feudal society, the continuation of the family was considered important, so pregnant women who died were believed to fall into a hell with a pond of blood.
It is said that when one encounters an obo, throwing a piece of cloth, such as a string with a billhook attached for men, or a gōkōsō (a type of women's handkerchief), tenugui, or a yumaki (a type of waistcloth) for women, it would divert the obo's attention and create an opportunity to escape.
In the Nishimatsuura District, Saga Prefecture and in Miyamachi Miyaji, Aso, Kumamoto Prefecture, they are called "ugume" and it is said that they appear at night and they would make people embrace a baby a night, but when dawn comes, they would generally be a rock, a stone tower, or a straw beater.
[11] Also, the ubume in Japanese legends is a bird that resembles the gull in appearance and voice and it is said that they would land on the ground and shapeshift into a woman carrying a baby and they would request "please hold on to this child" to people they meet and those that flee would be cursed with chills and fevers and eventually death.
[15][16] Typically, the ubume asks a passerby to hold her child for just a moment and disappears when her victim takes the swaddled baby.
[3] Many scholars have associated the ubume with the legend of the hitobashira,[17] where a sacrificial mother and child "are buried under one of the supporting pillars of a new bridge.
[19] Tokugawa-era artists[15] produced many images of ubume, usually represented as "naked from the waist up, wearing a red skirt and carrying a small baby.
"[15] Other illustrations of ubume are from Toriyama Sekien’s late-18th-century encyclopedia of ghosts, goblins, and ghouls, Gazu Hyakki Yagyō.