Key is a Japanese visual novel studio known for making dramatic and plot-oriented titles.

Key's debut visual novel Kanon (1999) combined an elaborate storyline, up-to-date anime-style art, and a musical score which helped to set the mood for the game.

Both Kanon and Air were originally produced as adult games, but this trend was broken with Key's third title Clannad (2004), released for all ages.

Key has worked in the past with Interchannel and Prototype for the consumer port releases of the brand's games.

Co-founder Jun Maeda is a prominent figure in the brand, having contributed to the planning, scenario, and music composition in the majority of Key's visual novels.

Before forming Key, the founding members worked for another visual novel development company called Nexton under the brand Tactics.

At the time of Dōsei's production, Tactics' first game, four of Key's original staff worked on the game: Itaru Hinoue as art director, Shinji Orito as musical composer, and Miracle Mikipon and Shinory contributing to the computer graphics.

Due to differing opinions between Nexton and most of the production staff in Tactics on how to produce the brand's next game, most of Tactics' staff left Nexton to pursue work in another publishing company where they could have the freedom to produce their next game.

[1] Baba gave the developers the freedom they desired, and they officially transferred to Visual Arts where they formed Key on July 21, 1998.

With the production of Key's debut title Kanon still in its early stages, a brand name had still not been decided on by the developers.

Works and Aniplex to produce the anime series The Day I Became a God[23] that aired between October and December 2020.

Key announced the development of three kinetic novels in October 2020: Loopers, Lunaria: Virtualized Moonchild, and Stella of The End.

[27] Key also revealed in October 2020 the multimedia project Prima Doll in collaboration with plastic model and figurine manufacturer Kotobukiya.

[31] A four-volume kinetic novel series for Prima Doll began with volume one released on April 28, 2023.

The first album on this label was Humanity..., though the only direct connection to Key's works is that it contains a remixed version of the opening theme to Air.

Each time, the concert lasted for two and a half hours and featured songs sung by Lia, Rita, Chata, and Tomoe Tamiyasu who have previously sung songs for singles and albums released under Key Sounds Label.

[40][41] A fifth concert called KSL Live World 2016: The Animation Charlotte & Rewrite was held in Toyosu, Tokyo on April 30, 2016.

[49][50][51][52] The products Key sells at Comiket are all related to the visual novels the brand produces.

1st Beat visual novel and partially wrote its scenario, in addition to providing the original concept for Summer Pockets.

Naoki Hisaya had worked as one of the main scenario writers for Kanon,[65] but once the project was complete, he left the brand.

Kai later headed the planning of Kud Wafter, as well as contributing on the scenario of Angel Beats, Harmonia and Summer Pockets.

[8][73] Chika Shirokiri, another outsourced writer who worked with Key on Little Busters!,[8][73] also wrote the scenario for Kud Wafter.

[8] Magome Togoshi had been with Key since before Kanon's release, working as one of the signature composers, but left the brand in October 2006[74] after contributing to the soundtrack of Little Busters!.

also featured three outsourced musical composers: Maiko Iuchi of I've Sound, Sōshi Hosoi, and Ryō Mizutsuki.

[78] Due to an influence by Leaf's visual novel To Heart released in 1997, the developers at Tactics created a simple formula for a game: a comedic first half with a heart-warming romantic middle followed by a tragic separation and finally an emotional reunion formed what is known as a "crying game" or "nakige".

Examples of this include: Kana: Little Sister by Digital Object, the Memories Off series by KID, D.C.: Da Capo by Circus, Snow by Studio Mebius (also under Visual Arts), and Wind: A Breath of Heart by Minori.

[78] Ryukishi07 of 07th Expansion wrote in 2004 how he was influenced by Key's works during the planning of Higurashi no Naku Koro ni.

[80] Ryukishi07 played Key's games as a reference, among other visual novels, and analyzed them to figure out the reason why they were found to be so popular.

This resulted finally with the Leaf and Key fans moving away from 2ch and forming again on the PINKchannel Internet forum.

"Mr. Nameless-dayomon"), a reference to the heroine Mizuka Nagamori from One: Kagayaku Kisetsu e who frequently ends her sentences with "dayo" and "mon".