Koihime Musou is a hentai game that tells the story of a Japanese student named Hongou Kazuto. Near the beginning of the game, he breaks a mystical mirror and is sucked into an alternate history of China during the Romance of The Three Kingdoms era (near the end of the Han dynasty). Everything is recognizable, except everyone speaks Japanese and all of the major players in the conflict are instead anime-style heroines - powerful generals shown to be capable of single-handedly taking on small armies. If it seems similar to the Dynasty Warriors franchise, it's effectively the same concept in a different genre.
Due to the manner of his appearance (out of thin air), his shiny clothing (a polyester school uniform), and strange style of speech (Japanese slang and borrowed English words), Hongou is assumed to be the anticipated "Messenger of Heaven" by the two generals who discover him, Kan'u and Chouhi, and they immediately swear fealty to him. Trapped in a village being attacked by the Yellow Turban rebels marking the opening event of The Romance of The Three Kingdoms historical novel, Hongou relents and allows his generals to rally the villagers in his name as the "messenger of heaven" in order to beat back the rebellion, cementing his place in the story.
Hongou takes on the role of Liu Bei (or Ryuubi in Japanese) by doing this, and ends up becoming the leader of the kingdom of Shu through a series of events that heavily reinterprets the original story. He is ultimately put into conflict against the Toutaku, Sougi (Gi), Sonken (Go), Enshou factions. Again, much like the Dynasty Warriors franchise, Koihime Musou also uses the Japanese names for the generals and nations in their retelling. It also maintains the Chinese concept of "personal" or "true" names reserved for close friends and family in order to permit more girly names for the characters, while still having a familiar "courtesy" name from the history books that everyone else used. Use of a person's true name without their permission resulted in serious insult, and is used to punctuate gags and emotional moments throughout the game.
The role of Ryuubi is taken on by the male player character Kazuto in the first game. In Shin Koihime Musou and beyond, the character of Ryuubi exists independently, and Hongou is free to ally himself with any of the main factions, allowing for multiple story campaigns. Initially armed with foreknowledge of the events during the Romance of The Three Kingdoms era that allows him to make certain correct large-scale tactical decisions, the majority of the military planning and city-building strategy is ultimately put on the shoulders of his strategist Shokatsuryou, making him more of an inspirational figurehead. Kazuto is trusting, friendly, and like many harem-style hentai games, desired by every allied female character to some degree. Unlike most harem games or anime series, due to the time period, fidelity is a non-issue. The supporting cast expect him to sleep around and take many wives. Kazuto is portrayed as being hopelessly letcherous, but with a heart of gold. In between battles at the home base, the player character can choose to spend time with up to two of the three main heroines, and up three of the many generals, prisoners, and entire defeated factions within his borders before forced to continue with the story.
Kan'u (True Name: Aisha)
Kanu Unchou is one of the first generals to swear fealty to Hongou in the hopes of restoring peace to the war-torn lands of China. She's a skilled combatant with her Green Dragon Crescent Blade as well as an able strategist. Her personality is very passionate, disciplined, and self-sacrificing, but she is also very modest and easily embarrassed. Aisha is one of the three main romantic interests and has a dedicated ending sequence if the player selects to spend time with her the most.
Chouhi (True Name: Rinrin)
The most child-like of the three main romantic interests, Rinrin is an orphan that was effectively adopted by Kan'u prior to both of them coming across Kazuto in the beginning of the game. While tiny, she is an exceptionally fierce warrior when wielding her Viper Spear and mowing down enemy soldiers, or fighting toe to toe with older and much more experienced generals. She loves to test her strength and is usually encountered sparring in all-out matches with the other immature Shu general, Bachou. Both tend to spend a lot of time together and tend to agree on food, policy, and military strategy. Even though she's a primary general in Kazuto's army, she is still a young girl and spends a good bit of time playing with Kouchuu's young daughter Lili, who looks up to her as an older sister. Rinrin also has a dedicated ending.
Shokatsuryou (True Name: Shuri)
Shuri is rescued by Kazuto and his two initial generals very early in the game from a Yellow Turban attack and joins as Shu's able military strategist and urban planner. While she looks young, she's unrivaled in terms of sheer strategic intelligence by almost any character in the game. She is very meek and unable to defend herself in battle, tending to stay back with Kazuto away from the front lines, or relying on stronger characters to protect her from attack. She spends most of her downtime reading recreationally under trees or playing strategic board games with other generals. She is the third of the main romantic interests, and also has a dedicated ending.
Chouun (True Name: Sei)
Initially something of an undecided mercenary looking to ally herself with the leader most likely to ultimately prevail, Sei does not initially join the Shu forces. When she does, she proves to be a capable general who is seen as something of a rival by Kan'u. She's arrogant, calm, provocative, and quite the lush. She is addicted to menma. She spends the majority of her free time with one of the few male characters in the game, Chousen. While off duty, she leads a secret double life, protecting the innocent in Kazuto's capital city as masked hero "Madame Butterfly".
Bachou (True Name: Sui)
The most tomboyish character in Shu, "Bachou the Splendid" is a rough, loud, naive girl who spends the majority of her time sparring, or caring for her horses. After her father is killed by Sousou's forces and her lands occupied, she joins with Hongou because she believes he can help her get revenge. Generally very happy and prone to getting into trouble with Rinrin, she is the least comfortable with Kazuto's polygamy of any of his generals, frequently calling him out a "demon pervert" among other things whenever he pays attention to her.
Kouchuu (True Name: Shion)
Initially head of her own small government, Enshou kidnaps Shion's daughter Lili in order to force her to confront Shu and risk her own soldiers instead. She is so impressed with Hongou's military performance and safe rescue of her daughter that she pledges fealty and allows him to annex her territory as she feels he can best defend it. She moves to the capital with her daughter and shares strategic and urban planning duties with Shuri. Shion is a motherly type the other generals look up to and often come to for advice, and along with Sei is the most overt about both her attraction to Hongou and comfort in sharing him with everyone else. While not necessarily powerful as some of the other generals, is so proficient and superhumanly fast with her bow that she is able to hold her own in close combat while still using a ranged weapon. She is an able strategist and will be the linchpin to late game combat for most players. Under her leadership and expertise, formations focusing on archers decimate when both on offense and defense.
Chousen is based on Diaochan, one of the "Four Great Beauties" of Ancient China and the only one alive during the Three Kingdoms period. The Diaochan of legend was said to have been "so luminously lovely that the moon itself would shy away in embarrassment when compared to her face." However, in the topsy-turvy world of Koihime Musou where all generals are beautiful women, the one beautiful woman in the original story is here presented as a gargantuan balding man with rippling muscles, pigtails, and wearing nothing but a small, pink thong. This was played up with the voice casting, where they hired Yuunagi Sakumi, also known as Norio Wakamoto, the man with one of the most penetrating voices in the industry. He is normally cast as villains, or gods, or as GPS Navigation systems. In Koihime Musou, the booming voice who lent gravitas to M. Bison, Nobunaga Oda, Castlevania's Dracula, DBZ's Cell, Xemnas, and Megatron is used effeminately to complete the picture of this unlikely "maiden". "She" too is in love with Kazuto, much to his disgust. Chousen (forcibly) allies himself with Shu in order to be closer to Kazuto. Chousen self-identifies as a woman, and sees the Shu generals as sisters. Quite likely the strongest character in the game, physically.
Enshou (True Name: Reiha)
The leader of the Enshou forces, Enshou is hubris personified. Prideful and arrogant, she doesn't believe she's capable of failure due to her noble blood and is quick to lay blame at the feet of others. She has aon ongoing rivalry with opposing general Sousou, and both women are sadistic and see their generals as tools and playthings. She also has the most unique plot arc in the game, as instead of interacting with Hongou, upon defeat she leaves on a grand adventure with her trusted officers looking for a hidden paradise. Checking in with her during downtime instead shifts the game focus onto her and her mostly hilarious self-contained vignettes crossing through other countries.
Bunshuu & Ganryou (True Names: Iishe & Toshi)
Rarely seen separately, Enshou's generals are a brash, foolish gambler, and a reserved, submissive strategist respectively (although both can hold their own in a fight). Previously bandits, eventually Enshou took an interest in them and made them her generals. They remain loyal vassals to her regardless of her ability to lead out of appreciation and genuine affection.
Sougi (Cao Wei) Generals
Sousou (True Name: Karin)
Sousou is a petite sadist with hair clips that appear to be tiny skulls. She demands complete submission from her generals and both rewards and punishes them sexually. She considers Hongou to be hideous and would like nothing more than his death for that reason alone. She's attracted to Hongou's primary general, Kan'u.
Kakouton, Kakouen & Jun'iku (True Names: Shunran, Shuuran & Keifa)
The Kakou sisters are Sousou's muscle on the battlefield as well as her playthings (as well as her cousins). They are fiercely loyal to her and only her. When General Kakouton takes an arrow to the face during a pitched encounter, she goes so far as to pull it out with her hand (along with the left eye it had pierced) while somehow maintaining her composure so as not to disappoint Sousou. Jun'iku plays the role of Sousou's pet and strategist, with a cat-eared hood and a strategic mind on par with Shu's best.
Songo (Sun Wu) Generals
Sonken (True Name: Renfa)
Having inherited the Songo army after the death of her elder sister Sonsaku in battle, Sonken has large shoes to fill, both in the eyes of her nation and her sister's strategist and advisor, Shuuyu. While her elder sister was pledged to conquer rival nations and bring about an age of peace, Sonken's willingness to compromise and her conservative nature puts her at odds with her own people at times. Having had to also be a role model for her little sister Sonshoukou (Shaoren), Sonken was forced to grow up fast. Fortunately she had people to rely on, including the Ninja-like head of her personal guard Kannei (Shishun), and the ditzy secondary strategist, Rikuson (Non). Both are loyal to Sonken as a leader and a person, not just due to her title and lineage.
Shuuyu (True Name: Meirin)
Shuuyu is the cold, calculating backbone of the Songo military machine. She is based on Zhou Yu. She disagrees with Sonken's policies, however remains loyal out of a sense of obligation she has to Sonsaku's family. Previously she served as a devoted advisor to Sonken's older sister Sonsaku (based on Wu warlord Sun Ce). Shuuyu willingly sends her wife Shoukyou and Sonsaku's widow Daikyou as gifts to Shu in order to seduce and spy on Hongou Kazuto, and they obey out of blind loyalty. (The twins are based on sisters Da Qiao and Xiao Qiao, respectively. However, in this rendition, elder sister Daikyou is a hermaphrodite.)
Totaku (True Name: Yue)
Initially presented as a cruel despot and the reason while Shu, Go, Gi, and Enshou join together in an Anti-Totaku alliance, it is revealed that things were not as they seemed to be. When finally confronted, Totaku is shown to be a weak and timid ruler. Hongou takes pity on her and her aide/strategist Kaku (Ei), and smuggles them out of the capital as simple prisoners without revealing their identities. Forbidden to give them actual freedom by his own generals or even allow word to spread that they're still alive, Hongou appoints them as his servants and abuses his station in order to have them dress up in period-inappropriate french maid uniforms. Both characters play up the cliched anime archetypes with Yue being the meek, submissive, lovey dovey "dere dere" character, while Ei is the classic cold and hostile "tsun tsun," only accepting the role of servant over death at all because of her devotion to Yue.
Ryofu (True name: Ren)
Ryofu as a general is a force of nature. Unconcerned with politics or leadership, or really anything at all people are aware of, she kills on command, and is easily a match for any two of the best generals in combat. She is considered the most skilled warrior in the three kingdoms. She maintains an economy of words, communicating the absolute minimum necessary whenever she must. Her own forces can barely control her, and with good reason: She's based on Lu Bu, known for killing two separate lords that had taken him under their wings as adoptive fathers. She's first encountered along with Chouryou (Shia), another of Totaku's generals and the female version of Zhang Liao, at Hulao Pass. A loyal but pragmatic general, Chouryou falls for Hongou's general Kan'u during combat, proving that love can indeed bloom on the battlefield.
Unlike most hentai games, Koihime Musou actually does have gameplay elements. While not complicated, when compared to other titles in the genre that are mostly limited to dialogue trees, Koihime Musou manages to marry legitimate gameplay with a complex plot. The player is tasked with meeting victory conditions in around two dozen battle scenarios throughout the game, ranging from completely wiping out the opposing army, to merely surviving for a set number of days against overwhelming odds until reinforcements arrive. The game allows the player to select various formations for their army, and they pit their formation against an unknown formation that the opposition commits to. As some formations are strong against some and weak against others, it creates essentially a Rock, Paper, Scissors dynamic to the combat. This is further complicated by the choice to attack, defend, or fire a volley of arrows at the opposing army, introducing an additional layer of RPS. The relative strengths of these attacks are increased or decreased prior to battle where the player decides what the composition of his army will be, focusing on Light Infantry, Heavy Infantry, or Archers.
Simplifying this combat while at first blush further complicating it is the selection of Generals that the armies enter battle with. One general leads the charge, and another hangs back to direct the army as a strategist. For the player, this means the general that enters the fray can use a unique special ability, while the strategist applies her expertise with various formations to increase or decrease their default effectiveness. As examples, using Kan'u as a forward general applies a morale boost to the troops causing them to generally be much more effective, while Chouhi and Bachou simply wade into battle every 4 or 5 days respectively and singlehandedly slay several thousand of the opposing force. Enemy generals also have skills, some of which can delay activation of the player's special abilities and/or deal direct damage. Shokatsuryou is not a warrior and won't cause direct or indirect damage as a field general, but when her special ability is used immediately before an opponent's ability she uses her advanced military tactics to negate their ability completely.
Shokatsuryou is also by far the most versatile strategic general, having an excellent rating with almost every formation, While brute force characters like Chouhi or Bachou are only very good with the most offensive "all-in" strategies, if that. Opponent generals are similarly limited in effective strategies, so players will find that the computer can be fairly predictable with most battles, alternating between the two or or three formations they're best at. In the event the player loses the battle, it permits a retry with additional reinforcements, making even the worst strategists eventual victors due to sheer attrition.
The traditional visual novel elements of selecting dialogue options are absent. The actual choices made in the game are about choosing to spend time with your generals and allowing the cutscenes to play out. Of the three main romantic interests, the one selected most often is the one who the player can select to end the game with. Any other selections in the game do not matter. If two of the girls are tied for most visits, the player can choose one of them to end with. Provided the player has beaten the game with all three previously, there is also a hidden harem ending.
Koihime Musou is atypical in that the resolution breaks the fourth wall completely. The motivations of the antagonists are kept secret for the duration of the game and only revealed right at the very end. The Taoist main villains and their conjured army of white-clad soldiers are revealed to be acting antagonistically only because they are aware of their role in the story: Their purpose in existance of being a foil for the player avatar, Hongou Kazuto. They seek to bring an end to the world of Koihime Musou by killing him and ending the story of the game. They rationalize that they will be victorious even if Hongou defeats them, as the plot will still conclude and the world will cease to exist because the player will stop playing. The fictional take on ancient China only exists in the imagination of the person experiencing it. The player is informed through exposition that victory (and salvation) for the characters is in the retelling of the story, potentially in a different way, and even dead characters can gain a measure of immortality by staying alive in the mind of the player. Ostensibly, the only true victory then would be for the series to be a success financially and cause the developer BaseSon to continue making more Koihime Musou games. With multiple "sequels" (in reality more like re-tellings) and an anime series, it seems that BaseSon succeeded.
Koihime Musou localization by MangaGamer was largely funded by Nexton, the developer's parent company, in a move atypical of most localized eroge titles, presumably to promote the franchise and anime to a larger worldwide audience (Usually the financial burden is shouldered by the localization company).
Keeping cost in mind, Nexton made the judgment call to omit the voice work from the final English release. The team at MangaGamer expressed their apologies to audiences for the decision, and tried to bring to light just how much it costs in licensing to bring games to western audiences. In Koihime Musou's case, top tier Japanese voice acting talent riddled the original Japanese release, with over two dozen well-known (and well-paid) actors lending their voices to the game as well as the anime. Including the existing voice work in the English-localized release would have ended up being the single largest expense of the entire project by a wide margin. The game was stripped of voices in order to keep it profitable. After lengthy discussions and negotation with Nexton, MangaGamer pledged prior to the release to restore voices to the game with a patch in the event that at least 2,000 copies of the game were sold. Without an advertising budget, on their blog, they instead encouraged fans to try to get two or three friends to purchase the game in order to reach that goal.
On April 6, 2012, well over a year after the English language release, MangaGamer quietly released the teased official voice patch for free, along with a number of bug fixes. Presumably the sales target was met, however the tactic used may have hindered more than helped sales. Soon after the release of the game, modders went to work implementing their own voice patch from the original audio files in the Japanese release, making the modified, pirated copies of the game potentially more attractive to consumers than the official voiceless release.