Until quite recently in rural Japan, yobai, or “night crawling” would have been an introduction to sex for many young people. While a young woman slept, a silent intruder would creep into her room, slide behind her and make his intentions known. If she consented, they would have discrete sex until the early morning, when he would have to slip out of the house as stealthily as he had slipped in.

The young man might be known to the girl and her family. Also, in a seasonal agricultural economy, farmers might have a number of laborers sleeping under their roofs sometimes, knowing that their daughters might be targets for yobai. In some cases, groups of friends would travel miles to neighboring villages, where the embarrassment of capture wouldn’t be as great, and each target a different girl.

In many cases, yobai would be conducted entirely with the knowledge of the girl’s parents. In fact, it was sometimes a prelude to marriage - parents would turn a blind eye the first few nights a young man secretly visited their daughter, but then he would be “caught”, and a more public courtship would begin...