Visual novel

A visual Novel is essentially a choose your own adventure book with background music, character visuals, pre-rendered backgrounds, and other variables made to engage a reader, or player, in a story. While not as common outside of Japan, visual novels have become more and more common in western markets and have been created by independent developers outside of Japan (see Four Leaf Studios).

Visual novels include from 1 to 50+ hours of "gameplay," as they feature multiple story lines that branch off to different endings. This isn't to be confused with kinetic novels, as those have one ending and storyline and are more reminiscent of a traditional book.

History
Visual novels originated from eroge, games in which pornagraphy was the main focus of the game. Beginning as far back as the 1980s, eroge was just porn for porn's sake, while having an anime art style in order to represent women. For the most part, these games revolved around sex in different situations with its ultimate goal being sex for one's own enjoyment. There is very little gameplay in these games.

Eventually, dating sims derived from eroge and focused more on the relationship with a girl rather than just sex with a girl. In dating sims, a player would go through the story, meet a girl, and build a relationship off of the various meetings the player has with said character. In later games, the player has multiple girls to choose from and each girl would have her own unique storyline. These types of games grew in popularity and eventually became visual novels.

Of course, games involving a female protagonist and multiple male relationships exist, too.

Adaptations
Visual novels, much like anime, aren't limited to a specific genre. They are a medium and should be treated as such. Adaptations of visual novels tend to be a safe choice to adapt as many studios {including Kyoto Animation, Shaft, and P.A. Works) have adapted anime from visual novels in various manners:


 * The "True Route": Adaptation in which a studio adapt every or several of the arcs of a visual novel and ends with the "True Route" of the game. Game mechanics (such as getting a bad ending before getting the good ending) can convolute the flows story of an adaptation as the mechanics no longer take affect. (examples: Clannad and Little Busters!)
 * Omnibus: Adaptations in which every route is explored and animated fully while resetting the story after an arc has finished. (example: Amagami SS)
 * Parallel Story: Adaptations in which multiple story lines happen at the same time which do or do not intertwine. (examples: Ef: a fairy tale of the two and Tachi ni Tsubasa wa Nai)