Japanese eroge, also known as H-games or hentai games, have their origins in the early 1980s, when Japanese companies introduced their own brands of microcomputer to compete with those of the United States. Competing systems included the Sharp X1, Fujitsu FM-7, MSX, and NEC PC-8801. NEC was behind its competitors in terms of hardware (with only 16 colors and no sound support) and needed a way to regain control of the market. Thus came the erotic game. The first commercial erotic computer game, Night Life, was released by Koei in 1982. It was an early graphic adventure, with sexually explicit images. That same year, Koei released another erotic title, Danchi Tsuma no Yuwaku (Seduction of the Condominium Wife), which was an early role-playingadventure game with colour graphics, owing to the eight-color palette of the NEC PC-8001 computer. It became a hit, helping Koei become a major software company.
Other now-famous Japanese companies such as Enix, Square and Nihon Falcom also released erotic adult games for the PC-8801 computer in the early 1980s before they became mainstream. Early eroge usually had simple stories, some even involving anal, which often led to widespread condemnation from the Japanese media. In some of the early erotic games, the erotic content is meaningfully integrated into a thoughtful and mature storytelling, though others often used it as a flimsy excuse for pornography. Erotic games made the PC-8801 popular, but customers quickly became tired of paying 8800 yen ($85) for such simple games. Soon, new genres were invented: ASCII's Chaos Angels, a role-playing-based eroge, inspired Dragon Knight by Elf and Rance by AliceSoft.
In 1992, Elf released Dōkyūsei. In it, before any eroticism, the user has to first win the affection of one of a number of female characters, making the story into an interactive romance novel. Thus, the love simulation genre was invented. Soon afterwards, the video game Otogirisou on the Super Famicom attracted the attention of many Japanese gamers. Otogirisou was a standard adventure game but had multiple endings. This concept was called a "sound novel".
In 1996, the new software publisher Leaf expanded on this idea, calling it a visual novel and releasing their first successful game, Shizuku, a horror story starring a rapist high school student, with very highly reviewed writing and music. Their next game, Kizuato, was almost as dark. However, in 1997, they released To Heart, a sweetly sentimental story of high school love that became one of the most famous and trendsetting eroge ever. To Heart's music was so popular it was added to karaoke machines throughout Japan—a first for eroge.
After a similar game by Tactics, One: Kagayaku Kisetsu e, became a hit in 1998, Visual Art's scouted main creative staff of One to form a new brand under them, which became Key. In 1999, Key released Kanon. It contains only about seven brief erotic scenes in a sentimental story the size of a long novel (an all-ages version was also released afterward), but the enthusiasm of the response was unprecedented, and Kanon sold over 300,000 copies. In 2002 a 13-episode anime series was produced, as well as another 24-episode anime series in 2006. According to Satoshi Todome's A History of Eroge,Kanon is still the standard for modern eroge and is referred to as a "baptism" for young otaku in Japan. Although many eroge still market themselves primarily on sex, eroge that focus on story are now a major established part of Japanese otaku culture. Oftentimes, voice actors who have voiced for eroge have been credited under a pseudonym.
There is no set definition for the gameplay of eroge, except that they all include explicit sexual content. This most often occurs as hentai scenes of the player character having a sexual encounter with other characters. Usually the sexual content is presented as a reward for the player's successful fulfillment of certain tasks. Like other pornographic media in Japan, erotic scenes feature censorship of genitalia, only becoming uncensored if the game is licensed and released outside Japan. Additionally, some games may receive an "all-ages" version, such as a port to consoles or handheld devices where pornography isn't allowed, which remove the sex scenes entirely.
Boys' Love (BL) games (also known as yaoi games) usually refers to eroge oriented around male homosexual couples for the female market. The defining distinction is that both the playable character(s) and possible objects of affection are male. As with yaoi manga, the major market is assumed to be female. Games aimed at a homosexual male audience may be referred to as bara. The eroge company Nitro+ has a division that produces exclusively BL games, known as Nitro+CHiRAL. They have produced the BL games Sweet Pool, Lamento: Beyond the Void, Togainu no Chi and Dramatical Murder, each one of the last two have been given a manga and an anime adaptation. A 2006 breakdown of the Japanese commercial BL market estimated it grosses approximately 12 billion yen annually, with video games generating 160 million yen per month.
Very few BL games have been officially translated into English. In 2006, JAST USA announced they would be releasing Enzai as Enzai: Falsely Accused, the first license of a BL game in English translation. Some fan communities have criticized the choice of such a dark and unromantic game as the US market's first exposure to the genre. JAST USA subsequently licensed Zettai Fukujuu Meirei under the title Absolute Obedience, while Hirameki International licensed Animamundi; the later game, although already nonexplicit, was censored for US release to achieve a 'mature' rather than 'adults only' rating, removing some of both the sexual and the violent content.
^Wood, Andrea. "Choose Your Own Queer Erotic Adventure: Young Adults, Boys Love Computer Games, and the Sexual Politics of Visual Play". In Kenneth B. Kidd, Michelle Ann Abate. Over the rainbow : queer children's and young adult literature. University of Michigan Press. pp. 354–379. ISBN978-0-472-07146-3.