Pornography in Japan has unique characteristics that readily distinguish it from Western pornography.^[1] Reflecting Japan's views on sexuality and culture, Japanese pornography delves into a wide spectrum of heterosexual, homosexual, and transgender sexual acts in addition to unique fetishes and paraphilias.

Starting with erotic stories and wood block prints from before the 20th century, Japanese pornography evolved into distinct subcategories. In addition to pornographic videos and magazines featuring live actors, there are now categories of pornographic manga (within Japanese comics), pornographic computer games (for both PC and game consoles), and pornographic anime (animated depictions of sexual activity).

By Japanese law, any lawfully produced pornography must censor the genitals of actors and actresses and up until the mid-1990s so was the depiction of pubic hair. Anuses are only censored at contact or penetration. This type of censoring also extends to hentai comics, video games, and anime. In the attempts to circumvent this type of censoring (and to cater to particular fetishes), actors and producers have featured subject matter unseen or rarely depicted in western pornography. Bukkake, gokkun, omorashi, and tentacle erotica are a few uniquely Japanese genres. Lolicon and its contribution to the controversy regarding the regulation of pornography depicting minors has been a major issue concerning free speech both inside and outside Japan.

Shunga or pornographic wood-block pictures were printed with all imaginable situations. The actual uses of shunga in the period are still debated, but probably resembled modern uses of pornographic materials, including masturbation and shared viewing with a lover.

After the Meiji Restoration in the second half of the 19th century, the publication of pornographic materials declined under government pressure.

In the late Taishō period and early Shōwa period, an artistic movement called Eroguronansensu, literally "erotic-grotesque-nonsense", occurred influenced by decadence works of Europe. Open sexual expressions were permitted in novels and manga but a strict control was applied on photographs and films.^[2] After World War II, the law against 'obscenity', Article 175, was the only official censorship law that remained in force.^[3]

Influenced by magazines like Playboy, pornographic magazines were printed soon after World War II. While Playboy's articles were about the American lifestyle; women were mostly non-Asian, interviews were with people largely unknown in Japan, and fashion and sport were American, it thereby spawned a fetish and a genre known as yōmono (literally "Western things").^[4]

In the early 1960s, several movie studios began producing "pink films". With censorship laws prohibiting genitals from being seen but otherwise free to express anything, these movies quickly diversified to fill all genres, including rape and bondage. Throughout the 1960s, the "pink films" were mainly produced by low-budget, independent filmmakers such as Kōji Wakamatsu. In 1971, the major studio Nikkatsu entered the pink film genre.

Starting in 1971, homosexually-oriented magazines began to appear, including Barazoku. Homosexual magazines tend to be tailored to particular segments of the population, such as Badi, which features younger adult males, Samson, devoted to chubby men, and G-men, featuring muscular men.

The proliferation of pornographic videos in the 1980s commonly called A/V (short for adult video) sold more videos because most Japanese families now had at least two television sets and VCRs. It is rumored, but not supported, that VHS became popular over Betamax format because large numbers of A/V were released in VHS format.^[5] Few A/Vs were sold in laserdisc format. Playing games on personal computers with no limitation on content except for censorship laws was sometimes viewed as being synonymous with playing bishōjo games, because so few Japanese people saw any reason to play video games on these platforms, as opposed to video game consoles.

In the late 1980s, the dōjinshi market expanded. It is estimated that about half of this market consists of pornography. Copyright problems plague the market, yet the dōjinshi market was a common place for one to start before making a debut in a professional magazine. Yaoi began in the dōjinshi market.

According to John Carr, a United Kingdom government adviser on Internet safety policy for children, two-thirds of all pedophilic images on the Internet in the late 1990s may have originated in Japan. He further commented, "We think that child pornography, in any form, promotes values and sends the message that it is OK to sexually abuse children. It helps pedophiles to justify their ideas or behavior and it desensitizes society as a whole." Since the law against child pornography in 1999, the proportion is now believed to be less than 2%. ECPAT believes that many child pornography producers have simply turned to producing anime or films featuring adults dressed as children.^[6]

Women in Japan are reporting being tricked into 'modelling contracts' and being coerced into performing in pornography.^[7] There have been calls for greater regulation of the industry.^[8]

A new guideline has been proposed that women pornographic actors have the right to prohibit the sale of videos in which they appear after five years from initial release date.^[9]

Under Article 175 of the Criminal Code of Japan people who sell or distribute obscene materials can be punished by fines or imprisonment. Article 175 was included in the original document in 1907 and remains relatively unchanged.^[10] Showing pubic hair and adult genitalia was once considered obscene.^[11] Video pornography routinely depicts explicit sex scenes with the participants' genitalia obscured by pixelization. The amount of censorship of the penis can vary. The publication of Waterfruit and Santa Fe by Kishin Shinoyama was likely the first publication that featured pubic hair. Many video production companies belong to ethical associations which provide guidance on what is acceptable and what is not. The Nihon Ethics of Video Association, the Ethics Organization of Computer Software and the Contents Soft Association are examples of three such organizations.

Japan's indigenous religion, Shinto (Kami-no-Michi), is based in animism, with a belief that supernatural beings dwell in nature. The gods and goddesses of Shinto are not repositories of morality or perfection; instead, they exist within nature and thus, sexuality is an innate part of life itself.^[12] Therefore, religious attitudes are no obstacle to the presence of pornographic material in Japan's society.

Possession of child pornography depicting real children is illegal in Japan since June 2014.^[13] Distribution of child pornography was made de jure illegal in 1999 after international pressure from the United Nations, UNICEF and other international organizations, although the law made a distinction between hardcore pornography and the softcore pornography that is widely available in Japan, such as at junior idol and lolicon media centers like Akihabara and Nipponbashi, and at most konbini, or Japanese convenience stores.^[14] Prosecutions have been made under the new law by prosecutors under Japan's unique legal system, resulting in some financial verdicts, with relative strictness of enforcement continuing to vary by prefecture.

In June 2008, a bill that proposed the imposition of a ban on child-pornography possession was submitted to the House of Representatives of Japan where it was brought before the Diet in September, but failed to pass.^[15] On July 15, 2014 penalties were added to the simple possession of child pornography as a result of the revision of the law.^[16]

In 1999, Milton Diamond and Ayako Uchiyama postulated that the rise of pornographic material in Japan from the 1970s onwards creates a decrease in reported violence.^[17]

In 2016 the campaign group Human Rights Now reported allegations that some women appearing in pornographic films had been forced to do so against their will.^[18] The group called for the introduction of legislation to regulate production companies and for help for any performers who had experienced abuse.^[19]

Among the various subgenres of Japanese pornography are the following:

Dōjinshi (often transliterated as doujinshi) or literally "fan works" often contain pornographic imitations of popular anime, games and manga.

Animated erotica (known in the West as hentai but in Japan as "adult anime") is a popular genre in Japan and generally maintains the same style of animation seen in other popular forms of Japanese animation (anime). The term hentai literally means "metamorphosis" or "transformation", but in alternate use and in context to the situation of lewdness, it means "perverse manner" or "pervert".

Adult-oriented games are a genre for video games in Japan. The genre is somewhat unknown outside Japan because of several problems, cultural and translational. Known as "bishōjo games" or "pretty girl games" (alternately spelled "bishoujo") in Japanese, the games are known under several names used by English fans, including PC dating-sim game, hentai game/H game, and so on. Companies such as JAST USA and MangaGamer are translating dating sims and visual novels into English for the fledgling market outside Japan. For adult video games in Japan, the rating of "18+" was coined by the Ethics Organization of Computer Software or Contents Soft Association. Rating of adult video games has not gone in Computer Entertainment Rating Organization.

Fanfictions, commonly found in websites, are not limited to fictitious characters and often use real live people as well, though these works would make little sense to those who do not see Japanese TV programs. Dōjinshi writers typically use the Internet to market their products by offering previews of new works, a secret address where buyers can find additional works, and a sample of their games. They also recruit new writers and artists online. Several exclusively adult oriented search engines exist to let someone find a site they are looking for, without having to search through commercial websites that list all keywords. Many works of dōjinshi are featured in websites that collect the art and let people look for free.

Many websites feature seasonal greeting pictures, often pornographic, from linked sites and friends who frequent their sites. A typical Christmas greeting picture on such sites features a Santa-girl in various stages of undressing. The twelve zodiac animals of Chinese astrology allow for variations on catgirls.

Magazines are, along with videos, popular media for pornographic materials. Magazines that contain pornographic manga or pictures are controlled, and feature age requirements for purchase. Many localities in Japan require pornographic magazines to be sealed when sold outside of adult bookstores. But it is not uncommon to find non-pornographic magazines that feature nudity. Many magazines, especially weekly tabloids, include nude images and photo spreads similar to page three girls featured in many western tabloids. So long as these images do not depict sexual organs or sex acts, they are not considered pornographic and, hence, are freely sold in public.^[22]

Confessional writings by both genders are a popular topic in men's and pornographic magazines.

Manga with a pornographic content targets both male and female audiences, and both male and female manga artists write pornographic works. This is more commonly referred to as hentai.

Many pornographic films ("Japanese adult video" or JAV) have titles that may suggest that they use minors, or suggest that they show the recording of an actual crime. However, titles that are circulated with the approval of Eirin, the Japanese film industry's regulatory body, are in full compliance with and do not break any Japanese laws. A common ploy is to have a part of a title replaced with a character, or to use a phonetically similar neologism. For example, a video about "19-year-old Girls Sex Party!" may be sold with a title like "1X-year-old Girls Sex Party!". The word "joshikōsei" (女子高生), lit. "high school girl", cannot be used as it would suggest a girl of 15 years or younger, who cannot legally act in a pornographic video. The homonymic neologism "joshikōsei" (女子校生), which can mean a "girl student", is used in a large number of titles to promote the product without breaking censorship laws. This fact may be seen in popular places of Japan such as Akihabara or Den Den Town at Tokyo and Osaka respectively.