Tattooing as a way of sealing a commitment

In Japan, between the seventeenth and eighteenth centuries, the practice of the irebokuro in the pleasure quarters.

Irebokuro means "inserted mole" and are tattoos of black dots as a symbol of sentimental attachment. Eventually the practice spread throughout the country, even among the upper classes.

The moles were giving way to more elaborate shapes, such as words or names, and have become known as kishoboriwhich means "tattoo offering" or "tattooed oath".

In addition to a promise of fidelity or love between two people, a kishobori could be a prayer or an oath dedicated to the gods. It could also be a promise that the individual made to himself.

https://es.wikipedia.org/wiki/Horimono_(tatuaje)#Tatuaje_penal_o_irezumi
Moriarty, Yori. (2015) : Irezumi Itai. Traditional Japanese Tattooing. Gijón, Satori Ediciones.
Pinheiro Maués, Juliana (2019): Bravos citadinos: estudo das representações da tatuagem em estampas de ator do kabuki de Utagawa Kunisada. Repositório da produção científica e intelectual da Unicamp.