Koei Co., Ltd. is a Japanese video game publisher, developer, and distributor founded in 1978. The company is best known for its historical simulation games based on the novel Romance of the Three Kingdoms, as well as simulation games based on pseudo-historical events.
The company has also found mainstream success in a series of loosely historical action games, the flagship titles of which are Dynasty Warriors (真・三國無双 (Shin-Sangoku Musō)) and Samurai Warriors (戦国無双 (Sengoku Musō)), the Musō (無双) series. Koei also owned a division known as Ruby Party, which focuses in dating sim games.
On April 1, 2009, Koei merged with Tecmo to form the Tecmo Koei Holdings holding company.  Koei changed its name to Tecmo Koei Games on April 1, 2010 by absorbing Tecmo. Tecmo Koei Games continues to use the Koei brand.
Koei was established in July 1978 by Yōichi Erikawa and Keiko Erikawa. Yoichi was a student at Keio University, and when his family’s rural dyestuffs business failed he decided to pursue his interest in programming. The company to this day is located in the Hiyoshi area of Yokohama along with Erikawa’s alma mater, and the company’s name is simply a spoonerism of the school’s.
The company initially focused on personal computer sales and made-to-order business software. In 1983 it released Nobunaga’s Ambition (信長の野望 Nobunaga no Yabō), a historical strategy game set during the Sengoku period of Japanese history. The game went on to receive numerous awards, and Koei produced several more such games set against the backdrop of world history, including Romance of the Three Kingdoms, set during the Three Kingdoms period of Chinese history, and Uncharted Waters (大航海時代 Dai Kōkai Jidai; lit. Great Navigation Era), set in Portugal during the Age of Exploration.
In 1988, Koei established a North American subsidiary, Koei America Corporation, in California. This subsidiary localized Koei games for export to all territories outside of Japan, as well as producing original games and concepts with the leadership of designer Stieg Hedlund, like Liberty or Death, Celtic Tales: Balor of the Evil Eye, Gemfire and Saiyuki: Journey West. After Hedlund’s departure, this subsidiary ceased game development in 1995, focusing instead on localization, sales and marketing.
A Canadian subsidiary, Koei Canada, Inc. was established in early 2001, and a European subsidiary, Koei Limited was established in early 2003 in Hertfordshire, United Kingdom. Koei also maintains subsidiaries in mainland China, Korea, Taiwan and Lithuania. Recently, Koei created a Singapore branch for game development such as Sangokushi Online.
All Koei operations in English in turn ceased as of 2012, with the previously unannounced closing of Koei’s North American support forums and website.
Koei’s Ruby Party division specializes on games labeled as Neoromance: GxB dating sims, usually with extra side-quests. Out of the three Neoromance series, the best known is Angelique, which has been in production since 1994. Harukanaru Toki no Naka de is a newer Neoromance hit, with many sequels and an anime TV series based on it. The newest game in the series, Kin’iro no Corda, is gaining popularity partially because the manga series it was based on, has been recently licensed by Viz for English language publishing. It gaining more popularity though, and an anime TV series based on it began airing in October 2006. A sequel was also released on the PlayStation 2 in March 2007.
On September 4, 2008, Koei announced that it was in talks to purchase ailing competitor Tecmo. They have agreed in November 2008 to merge on April 1, 2009 to form Tecmo Koei Holdings. On January 26, 2009 the two companies approved the merger, the holding company formed on April 1, 2009 as planned.
On April 1, 2010, Koei absorbed Tecmo and renamed itself Tecmo Koei Games.  Koei Canada was also renamed Tecmo Koei Canada on April 1, 2010, while Koei’s subsdiairies in the United States, Europe and Korea already had their names changed months before the Japanese parent.  On March 15, 2010, the developing operations of Koei and Tecmo were spun off as new companies under the names of Koei Co, Ltd and Tecmo Co, Ltd respectively, but they were integrated into Tecmo Koei Games the following year, on April 1, 2011.  Koei continues as a brand within Tecmo Koei Games.
Games by Koei
Koei has built a large base of franchises, and has developed on various consoles and computers. Below is a list of game series developed by Koei.
- Bladestorm: The Hundred Years’ War An action/strategy game based on the Hundred Years’ War between England and France. (For the PlayStation 3 and Xbox 360).
- Croc series (Japanese version of all Croc games distributed by Koei) released for the PlayStation.
- Crimson Sea (initially released for Xbox in 2002, whereas its sequel was released for PlayStation 2 in 2004).
- Destrega A unique 1 vs 1 fighter produced for the PlayStation system.
- Dynasty Warriors 1 – 7 (as well as expansions ‘Xtreme Legends’ for 3 – 5, ‘Empires’ for 4 – 6, plus a Game Boy Advance, a Nintendo DS and three PlayStation Portable games) (真・三國無双 Shin-Sangoku Musō; spin-off of Romance of the Three Kingdoms).
- Dynasty Warriors: Gundam For the PlayStation 3 and Xbox 360, it is based on the mechanics of Dynasty Warriors and Samurai Warriors, only using the Mobile Suit Gundam franchise as its base. (ガンダム無双 Gundam Musō).
- Fist of the North Star: Ken’s Rage for the PlayStation 3 and Xbox 360.
- Fist of the North Star: Ken’s Rage 2 for the PlayStation 3, Xbox 360, and Wii U
- Mystic Heroes for the Nintendo GameCube and PlayStation 2.
- Ni-Oh (PlayStation 3 game, movie tie-in). (canceled?)
- One Piece: Pirate Warriors for the PlayStation 3.
- Prey the Stars exclusively released for the Nintendo DS.
- Samurai Warriors, Samurai Warriors 2, and Samurai Warriors 3 (as well as an Xtreme Legends expansion to both, and Empires expansion to 2, a PSP game, Samurai Warriors: State of War, and Samurai Warriors: Katana for the Wii.) (戦国無双 Sengoku Musō).
- Stop That Roach! Action/Puzzle game released in 1994 for Game Boy.
- Warriors: Legends of Troy is a Koei Canada game which was announced at E3 2009.
- Warriors Orochi For the PlayStation 2, PSP, PC and Xbox 360, it is the first Koei crossover title, featuring characters from the Dynasty Warriors and Samurai Warriors games. (無双OROCHI).
- WinBack Third person shooter game for Nintendo 64 and PlayStation 2.
- Trinity: Zill O’ll Zero exclusively for the PlayStation 3.
- Warrior Orochi 3 Hyper exclusively for the Wii U
- Genghis Khan series.
- Liberty or Death – Based on the American Revolutionary war.
- Nobunaga’s Ambition series – published on various platforms.
- Romance of the Three Kingdoms I to XI released on the MSX, MSX2, NES, SNES, Genesis, Amiga, PC-Engine CD-ROM, Sega Saturn, PS1, PS2 and PC – turn based strategy games
- Rise of the Phoenix – Based on the wars of the early Han and Chu dynasties in China, released on the SNES.
- Bandit Kings of Ancient China – Released on the Nintendo Entertainment System, MS-DOS, Amiga & Macintosh.
- Celtic Tales: Balor of the Evil Eye – Medieval fantasy simulator.
- Gemfire – Medieval fantasy simulator.
- Genghis Khan
- Kessen, Kessen II and Kessen III – Real time strategy games for the PS2 set in Feudal Japan and China during the Three Kingdoms period.
- L’Empereur – Turn-based strategy game released on the Nintendo Entertainment System
- P.T.O.: Pacific Theater of Operations
- P.T.O. II: Pacific Theater of Operations
- P.T.O. IV: Pacific Theater of Operations
- Naval Ops: Warship Gunner 2
- Nobunaga’s Ambition series – published on various platforms.
- Operation Europe: Path to Victory – A strategy game set in Europe during World War II
- Romance of the Three Kingdoms
- Teitoku no Ketsudan (PTO: Pacific Theater of Operations in North America) – Pacific War strategy games.
- Aerobiz – Airline business simulator series.
- Top Management – Business simulator series.
- Top Management II – Released on the Super Famicom, Microsoft Windows PC and NEC PC-9801.
- Winning Post – Thoroughbred horse racing management and horse breeding simulator series.
- Pop Cutie! Street Fashion Simulation – fashion design and business management simulation.
- Leading Company – Video cassette recorder business simulator.
- Angelique (アンジェリーク)
- Danchi Zuma no Yuuwaku
- Harukanaru Toki no Naka de (遙かなる時空の中で , translates to From a Faraway Time)
- Kin’iro no Corda (金色のコルダ, translates to Golden Corda)
- Neo Angelique ~Abyss~ (ネオアンジェリーク), a spin-off of the Angelique series with all new characters
- Night Life
- Bandit Kings of Ancient China
- Brandish (Super NES port)
- Danchi Zuma no Yuuwaku
- Inindo: Way of the Ninja (for Super NES) Also part of Rekoeition series
- Nobunaga’s Ambition
- Saiyuki: Journey West (西遊記 Saiyuki)
- Sangokushi Eiketsuden, Sangokushi Koumeiden, Sangokushi Sousouden (as Tactical RPG)
- Soul Master (ソウルマスター)
- Gitaroo Man (As well as a PlayStation Portable version called Gitaroo Man Lives!)
- Ishin no Arashi First game of Rekoeition series.
- Inindo: Way of the Ninja 伊忍道 打倒信長
- Uncharted Waters (大航海時代 Dai Kōkai Jidai; lit. Great Navigation Era) – Based on the Age of Discovery.
- Taikō Risshiden （太閤立志伝）
- Saihai no Yukue (采配のゆくえ)
Games published by Koei in Europe
- Disgaea series
- Dynasty Warriors 3
- La Pucelle: Tactics
- Atelier Iris series
- Phantom Brave
- Makai Kingdom: Chronicles of the Sacred Tome
- Colosseum: Road to Freedom
- Shin Megami Tensei: Persona 3 and Persona 3 FES
- ^ a b c d “Official report of Tecmo Keoi Holdings for the dissolution of Tecmo and Keoi development studios”. Tecmo Koei Holdings. 2011-02-07. Retrieved 2012-12-05.
- ^ 
- ^ Thorsen, Tor (2008-09-04). “Tecmo, Koei in merger talks”. GameSpot. Retrieved 2008-09-21.
- ^ Ashcraft, Brian (2008-09-04). “Report: Tecmo And Koei In Talks To Merge”. Kotaku. Retrieved 2008-09-21.
- ^ Tecmo and Koei to Merge in April 2009
- ^ Koei Tecmo Reveals Its New Company Logo (Looks Familiar)
- ^ “Tecmo Koei Company History”. Tecmo Koei Holdings. Retrieved 2012-12-05.
- ^ “TECMO KOEI HOLDINGS CO.,LTD. Announces Merger between Subsidiary and Sub-subsidiaries; Announces Business Transition between Subsidiaries”. Reuters. 2011-02-07. Retrieved 2012-12-05.
- ^ “Genghis Khan – MobyGames”. Retrieved 2009-02-01.
- ^ “Genghis Khan II: Clan of the Grey Wolf – MobyGames”. Retrieved 2009-02-01.
- ^ “Bandit Kings of Ancient China – MobyGames”. Retrieved 2009-02-01.
- ^ Dembo, Arinn; Aye, ‘Tis a Bonny Land Indeed: Koei explores the Emerald Isle’s Myth and Magic in CELTIC TALES, p. 214. Computer Gaming World, Issue 134, September 1995