Brown Wooden Door Near Body of Water

Yobai is a Japanese practice of “night crawling.” It is an ancient Japanese culture practiced by young Japanese men and women. 

It used to be a common practice in many rural areas in medieval Japan and continued even during the Meiji era (October 23, 1868 to July 30, 1912) and until the mid-1950s. It is unclear, though, if the tradition is still being practiced in some areas of Japan today. 

What is the history of Yobai?

White Wooden Closed Door

Yobai is referred to by many in the modern world as a weird sexual tradition. It is believed that the practice of Yobai existed about 1400 years ago. 

It is said that the term yobai is originally a verb that means “to repeatedly visit.” It comes from the words “Yo” which means night and “bai” which means crawl. The term, therefore, literally means “night crawling,” or “night and “crawl,” as it is now being written to represent folk etymology (changing of an unfamiliar term to a familiar one). 

The practice of yobai involved an unmarried man creeping into the house of an unmarried woman, waking her up and if she did not mind, they would indulge in passionate sex until the morning. 

This was done while the rest of the girl’s family was sleeping nearby or more often in the same room. 

The young Japanese man would often be wearing a tenugui (cotton clothy) to conceal his face. This was to protect his identity should his sexual advances be rejected by the young woman. 

During the era when yobai was aggressively practiced (it was widespread in rural areas), most Japanese houses only had one room. In certain instances, a room was only divided, at the best, by paper screens. Thus, night crawling was conducted with the understanding or unspoken consent of the girl’s parents and family members. 

It was common practice during that time for the young Japanese man to urinate along the bottom of the door of the woman’s house. This prevented the door from squeaking when opened and helped the young man from being detected by the girl’s parents and family. 

Sometimes, the young man would already take off his clothes before crawling into the girl’s house so, just in case he got caught, he would not be mistaken for a burglar. It was once considered illegal to attack a naked burglar because of the idea that he probably was engaged in “yobai” instead of being a thief. 

After obtaining the consent of the girl’s father, the young man would visit the young girl several times to have sex. After the first or second time, yobai could be discontinued by either side. 

On the third time, though, the family of the girl could barge in and “discover” what the couple was doing. At this point, yobai would be considered known to the public, and the couple was considered to be married. 

If the young woman got pregnant, they needed to get married. It had always been the hope of the woman’s parents that yobai  would eventually lead to marriage. 

The practice of “night crawling” varied among areas. In some areas, only women past puberty , married, or unmarried could be night crawled by men who were also past puberty, married, or unmarried. The men could come from the same village as the women or  they could also be travelers, or from other villages. 

In a closed-type yobai, only men from the same village as the women could practice the tradition. 

What were alternatives to Yobai?

View of Building Exterior

Omiai or “see-meeting can be considered as an alternative to yobai. Omiai means “see-meeting” or in simple terms – a Japanese young man and woman of marrying (25 years old for women and 30 years old for men) ages would meet, see if they got along, and if they did, got married within a few months. 

Omai was a formal affair in ancient Japan, and often planned by family members with the hope that the practice would end up in marriage. In yogai, it was also the wish of the woman’s parents that the practice end in marriage.

Both omai and yogai are acceptable steps that could lead to marriage. While night crawling had an immoral connotation, omai was a “cultured” way of meeting a future spouse. 

Mikka kasei or trial marriage, another alternative to yogai is a traditional practice wherein the bride spent two nights with the groom and returned to her home on the third day. If the bride was considered as a satisfactory spouse, there was a wedding. If she was rejected, she remained at home. 

Why is Yobai Illegal Today?  

Yobai is today considered immoral and is no longer practiced in Japan. Several decades ago, though, it was still being practiced, but not as common, in some rural areas in the country.

Yobai is already considered extinct in modern Japan. The practice only remains alive in the “yobai”-inspired adult clubs where male patrons can “sneak” into the room of a prostitute or stripper offering yobai services.  The night crawling tradition also remains active in erotic fiction and Japanese pornography.