What is an ancient tooth girl?

Grandma: Also known as Sister-in-law, this is a kind of woman who specializes in human trafficking. This kind of tooth girl not only runs away from official positions, but also woos rich people privately. In Song Dynasty, Wu's Dream once said: The official's house, the rich family, wants to buy concubines, singers, dancers, cooks, needlework, ladies-in-waiting, officials, private sisters-in-law and bigwigs. Remember clearly the professional characteristics of her sister-in-law. Later, until the Qing Dynasty, it was still very popular for old ladies to buy maids and concubines for others. In A Dream of Red Mansions, Jia's maid made a big mistake and asked a "human tooth" to take it away and sell it.

Literally explaining "tooth" means accusing the introducer between the buyer and the seller, which means "mutual", or "tooth" means "mutual". Tooth wives generally run the profession of matchmaker, and matchmakers often do the business of tooth wives, so that they can work part-time with each other and greatly improve economic benefits.