There's a story with varying details in Chēzang of two mortals who loved each other dearly, but one the mistake of praying for the blessing of the mercurial goddess Lau, for their relationship had not been one of official status, but after remaining together through the hardships they'd faced would be seen in public as a couple for the first time during Lau's festival. (reasons for the secrecy of their relationship vary through time, usually either due to both being women or due to differences of status)
Lau, goddess of alcohol, fermentation, and change, is notorious in many stories for blessing or cursing drunken revelers in the matters of love. In this instance, envy of the petitioner's beauty (or depending on the telling, a sense of disrespect or a simple dislike of the unchanging nature of their relationship), led Lau to instead curse the asker as she made her way to the festivities, robbing her voice and changing her appearance. In some versions the woman's appearance is changed to that of a stranger, to cause her partner to believe she had been abandoned, perhaps out of shame; in others she appears as a monstrous demon.
Instead of shattering their relationship, she was recognized by the woman who would know her love no matter the form, embracing her regardless.
Sho, god of marriage, promises, and the hearth, saw this unfold and undid his sister Lau's curse, and declared them married himself.
A tradition was born, celebrating their display of love: a masquerade in which partners ostensibly prove their love and the harmony of their souls by being able to recognize their partner even without being able to see their face.
