For centuries, Japan has deliberately isolated itself from the rest of the world, which has led to the formation of a deeply-rooted traditional society that is male-dominated and highly moralistic. This has caused considerable oppression on women and the lower classes.

Surprisingly, this does not necessarily mean that they are experiencing sexual repression. Instead, it indicates that they are conducting sexual experiments behind closed doors in order to compensate for the strict social norms.

Here are 5 interesting facts about ancient Japan that might surprise you.

The samurai carried pornographic materials with him as a lucky charm.

The classic woodblock art of pornography has been highly sought after in Japan for centuries. It was not until modern times that the emergence of pornographic photography gradually curbed its popularity.

It has many uses, some of which are predictable, such as stimulating the sexual desire of one's partner, or being used as an aid for masturbation by those who are unable to enjoy sex with their actual partners, such as traveling salespeople.

However, around the "pornographic images", certain beliefs gradually emerged and their uses expanded accordingly. Among them, the most intriguing one might be the belief based on the samurai: possessing pornographic images on the battlefield could somehow protect them from being killed.

To be fair, pornographic images from the Edo period may differ somewhat from contemporary pornographic works, as many of them demonstrated considerable artistic value, especially during the peak of the Edo era.

Homosexuality is acceptable (if you are male)

Surprisingly, in a deeply patriarchal society, male homosexuality exists in various forms and is widely accepted by society. Similar to some ancient Western cultures such as ancient Greece and ancient Rome, it is not uncommon for married men to have male lovers, as long as they are the ones actively involved in the sexual act.

These relationships are asymmetrical. The superior party is usually much older than the subordinate party, often being a pre-adolescent boy or a young person. The younger party usually gains financial rewards from this relationship.

Another common and asymmetrical homosexual relationship is that between Buddhist monks. Older monks often choose younger monks as their lovers. These two types of relationships are frequently depicted in the pornographic prints mentioned in the previous text.

Unplanned sexual activity is also acceptable (if you are a man)

The law allows men to have mistresses, and to some extent, men should have them. The reason is that the sexual satisfaction of either party is not regarded as a marital obligation. The purpose of marriage is procreation, and this is the sole requirement for marital sexual behavior. For all other sexual needs, there are varying degrees of sex workers, concubines, or, as mentioned before, young children.

This attitude has contributed to the prosperity of the prostitution industry. At one end are the high-class prostitutes and geishas, who mainly engage in performances. At the other end are the low-class prostitutes, whose income is only enough to make a living.

The sexual needs of married women have not been given the attention they deserve. People expect them to be absolutely faithful to their marriages, at least on paper. In reality, as long as it is done with reasonable caution and without resulting in pregnancy, upper-class women can usually tolerate extramarital affairs.

However, there is one thing that is unacceptable for anyone, and that is to have romantic feelings for one's partner. Or, as a writer in the 1930s put it: "According to traditional moral concepts, falling in love is regarded as a sign of mental and moral weakness."

The chastity of geishas has sometimes been sold, and sometimes more than once.

The flower-picking ceremony is called "mizuage" and it is the most important moment in the coming-of-age ceremony for young geishas. This ceremony is funded by a sponsor, who then personally takes away the virginity of the young geisha.

The best-selling book "Memoirs of a Geisha" (which has also been adapted into a film) once described this custom. For centuries, this practice has remained prevalent and has only been banned along with other forms of prostitution in 1959. "Shounen" is not only an initiation ceremony for young women but also a lucrative and often unknown business.

A true geisha, unfortunately, came of age in the 1950s when the custom of geisha was just being banned. In her autobiography, she described how she was repeatedly subjected to the terrifying "water shower" with various customers, and all the customers were convinced that she was a true virgin.

They are completely obsessed with sex toys.

The pornographic prints also reveal the widespread use of various sex toys beneath the veneer of moralism. Among them, a wide variety of artificial penises were commonly used. The most common type was the "harigata" (a hollow penile-shaped device made of animal horns, shells, leather, wood, or even pulp, used for insertion into the vagina or anus). Worn-out artificial penises and double-headed artificial penises were also frequently depicted as versions for heterosexual, homosexual, or group sex.

Other commonly used toys include small balls that can be inserted into the vagina to provide additional stimulation during sexual intercourse, as well as various penile rings and armor-like covers placed around the penis to enhance erection and increase the stimulation for the recipient.