Oshiragami - Oshiragami

Japanese: おしら神 - おしらがみ

...In addition, in the Kanto region and north, as sericulture spread, the story of the origin of the "horse girl marriage" was passed down, in which a horse fell in love with a rich man's daughter and they both died, and a silkworm was born from their bodies. This story comes from a ritual text recited by a shrine maiden who took part in the festival associated with the belief in Oshiragami as a silkworm god, and its origins were introduced from China. Also, since the most distinctive feature of a horse is its coat color, special attention was paid to it, and white horses in particular were offered to gods as sacred objects and were also used by nobles to ride. ...

From [Sericulture]

…The Otogi-zoshi Kahiko is one of them. The Oshira-gami of the Tohoku region also has an aspect as a god of sericulture, and the Itako's Oshira-saibun, which tells the story of a marriage between a horse and a human girl, also explains the origin of the silkworm god and the origin of sericulture. Oshira Belief [Komatsu Kazuhiko]. …

*Some of the terminology that refers to "Oshirakami" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…なお，関東以北では養蚕の伝播に伴って，長者の娘に馬が恋してともに死し，その死体からかいこが生じたという〈馬娘婚姻〉の由来譚を伝えている。これはかいこ神としてのおしら神信仰に伴って，その祭礼にあずかる巫女（みこ）の祭文に語られるところからきたもので，その源は中国からの伝来である。　また馬は毛色がもっとも特徴となるので注意がはらわれ，ことに白馬は神聖なものとして神祭に供せられ，また貴人の乗用ともなった。…