When Ordinary High-School Student Kazuto Hongo chases after a thief, who steals and breaks an ancient mirror at his school campus, he's transported back to ancient China. Are we good so far? Now, take the Romance of the Three Kingdoms story and Gender Flip nearly all male characters from the original epic into action girls of varying degrees of affection for Kazuto, and you get the perfect harem Visual Novel called Koihime Musou, developed by BaseSon. All principal heroines in the game are expies of the (male) generals from the original epic and the former's names are derived from the latter's by reading the original Chinese characters in their names as kanji. Additionally, all of them have a true, "private" name usually reserved for close friends, and several sport a courtesy name. European eroge publisher MangaGamer acquired the localization rights and released an English version on February 28, 2011.A remake of the visual novel Shin Koihime Musou was released with more characters added in from Romance of the Three Kingdoms and following suit by genderflipping them. Not only does it pay more attention to the original epic but it also allows players to choose which faction to ally with, rather than the preset one in the original game. A third and possibly final installment for the visual novels was released on July 23, 2010, entitled Shin Koihime Musou ~Moeshouden~, with the intent on dropping the battle sequences found in prior games for the purpose of focusing entirely on the Unwanted Harem aspect.Two other games exist in the franchise. The first one, Otome Taisen Sangokushi Engi, is a (alas, Japan-only) fighting game for arcade machines and PC. The second, Web Koihime Musou: Battle Maidens, is a web-based strategy game, free to play with microtransactions. It's been jokingly said that it is like Evony, except that it actually has girls. Plans to release the game overseas crashed abruptly when Beanfun, the distributor, had its Europe and US branches closed by Gamania, its parent company.The animated adaptation turns it into Yuri Fan bait by removing Kazuto altogether: there are actually very few notable men in any of the episodes. The anime's plot is secondary to gratuitous but surprisingly classy fanservice and keeps very little from the original novel. It basically consists of the expies of the "Five Tiger Generals" (google it already) coming together from across China to band against the anarchical rule of generic bandits.The anime based on the first game aired in the summer of 2008, and a second season Shin Koihime Musou aired in the fall of 2009. The third season, Shin Koihime Musou ~Otome Tairan~ aired in the spring of 2010. Prior to Shin Koihime, an animated follow-up OVA was released with the seventh DVD volume, set in a modern Japanese high school (but without The One Guy again). A sequel to the OVA was released on July 7, 2010, where the characters went on a trip to a southern island.Depending on region, the broadcast episodes can legally be seen for free at Crunchyroll:Spiritual Successor Sengoku Koihime, is set during the Sengoku period.Compare Ikki Tousen. Especially since, as of 2010, Koihime and Ikkitousen are collaborating on the basis of their similar setups.For individual character tropes, see the full character list.
Tropes in relation to multiple characters or the franchise: