[[quoteright:215:https://static.tvtropes.org/pmwiki/pub/images/rsz_4banshiryuu_scan_5337.jpg]]
->''This tale is set on Earth, far in the future...''

''Seihou Project'' (西方, where "Seihou" means West or Western) is a series of Doujinshi BulletHell Shoot 'Em Up games, developed by Amusement Makers. Known primarily as the sister series to the massively popular ''Franchise/TouhouProject'', the Seihou Project puts an emphasis on memorization and reflexes by focusing on less numerous but faster bullets compared to its sibling series. Notably, ZUN, the creator of ''Franchise/TouhouProject'', was involved in the creation of the first two Seihou games as a member of Amusement Makers, as its BGM composer.

In a distant future, Earth has fallen into near ruin after its natural resources are depleted, leading to the destruction of the environment and the extinction of nearly all vegetation on the planet. Driven to the brink of destruction, humanity finds its sole hope in the only surviving genus of plants left on Earth: the cactus. Erich, the chairman and founder of Cactus Company, heads the research to extract energy from cacti, discovering a miracle energy thus named Saboten Energy. However, while possessing power beyond even atomic energy, Saboten also proves to be extremely difficult and dangerous to control, causing large-scale accidents and nearly pushing Cactus Company to the verge of annihilation. Decades later, the Cactus Company manages to perfect the use of Saboten Energy, using it to slowly restore the environment, allowing humanity to bounce back.

The Seihou games chronicle the adventures of VIVIT, a [[SuperPoweredRobotMeterMaids maid-type combat android]] powered by Saboten energy, as she goes on errands given to her by her master Erich. She is later joined by Hirano Sakurasaki, a {{Miko}} who serves as the secondary playable heroine in ''Banshiryuu.''

There are currently three games in the Seihou series as well as some extras released to celebrate the series:

* SH 01 ''Shuusou Gyoku'' (2000)
* SH 02 ''Kioh Gyoku'' (2001)
* SH 03 ''Banshiryuu'' (2004; A radically-different UpdatedRerelease came in 2008)
* ''VIVIT-99'' (2019), a [[Main/WebGames Browser Game]] spinoff influenced by battle-royale style games (specifically ''[[VideoGame/{{Tetris}} Tetris 99]]''). Was taken down after a day to be released with extra features in the future, though it can be played if one buys the [[Main/BonusMaterial thin book]] commemorating Banshiryuu's 10th anniversary..
* ''Ragnus X Docking'' (2020), another April Fools Browser Game, featuring Lagunas and Yuuta.

Although not officially connected, ''Samidare'' is regarded as a SpiritualSuccessor to the Seihou series.

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!!This game series contains examples of:

* AfterTheEnd: And humanity managed to rebuild itself.
* AmazingTechnicolorBattlefield: The final stage of ''Shuusou Gyoku'', which apparently takes place in a dimension of ''non-physical concepts.''
* AprilFoolsDay: The date in which ''VIVIT-99'' and ''Ragnus X Docking'' were released.
* ArtificialStupidity: The A.I. of ''Kioh Gyoku'' is not intelligent in the slightest. It takes a while for the opponents to even move away from the bullets, and some attacks (such as Morgan and Erich's EX attacks) can kill them easily and quickly. [[FinalBoss Muse]] is only a difficult boss because her defense was ''hugely'' increased for the fight.
* BalancePowerSkillGimmick: In the C74 version of Banshiryuu, VIVIT-r-A is a balanced spread and homing type, VIVIT-r-B is a powerful laser shot with the most powerful bomb, and Hirano-A has a strong unfocused shot, weak focused, and the weakest bomb in the game. Hirano-B has the interesting gimmick of moving ''faster'' when focused. Her unfocused shot tilts when you move, and her focused shot is homing, but you need to go closer to the target.
* BatmanCanBreatheInSpace: Stage 5 of ''Banshiryuu'' takes place in outer space, despite the player characters not being in a spacesuit or vehicle of any kind. It's justified for VIVIT, who is an android, but Hirano...
* BeamSpam: Erich is infamous for his infuriating use of homing lasers. It goes double for your opponent if you [[GameBreaker play as him.]]
* BossRush: The extra stage of ''Banshiryuu'' has you fighting ''all'' the characters from ''Kioh Gyoku'', one after another, culminating in a battle against [[GiantSpaceFleaFromNowhere Icarus.]]
* BrutalBonusLevel
* BulletHell
* TheCameo: [[Franchise/TouhouProject Marisa and Reimu]] appear as {{Superboss}}es in the extra stage of ''Shuusou Gyoku''. [[Franchise/TouhouProject Yuuka Kazami]] appears as an unlockable player character in ''Kioh Gyoku''. VIVIT herself (along with Gates) appears as the boss of ''Samidare'''s Extra Stage (which also features [[Franchise/TouhouProject Mai and Yuki]] as mini-bosses.)
* ChildSoldiers: Mei and Mai, but also Marie, who is heralded as a military legend despite being a retired soldier at the age of ''19.''
* ColonelKilgore: Gates.
* CompositeCharacter: Muse is essentially [[Franchise/TouhouProject Sakuya, Alice, Remilia, and Patchouli]] rolled up into one character, except she [[OlderThanTheyThink predates all of them (except Alice.)]]
* CrapsackWorld: Although the world is slowly recovering from its environmental crisis, nearly all of the cast are involved with the military, either being PrivateMilitaryContractors or soldiers, which makes it clear that even TheEndOfTheWorldAsWeKnowIt hasn't eradicated wars. And then there are Mei and Mai, who are ChildSoldiers at the age of ''five.''
* DarkerAndEdgier: If you compare it to [[Franchise/TouhouProject Touhou.]]
* DavidVersusGoliath: [[RobotMaid VIVIT]]/Hirano goes up against stealth jets, HumongousMecha, or dreadnought space battleships. The only time when there isn't a huge size difference is when you're fighting either Muse, Yuitia, Icarus, or the ''Touhou'' cameo characters, and they're all far stronger than any other opponents.
* DeflectorShields: Serves as health in ''Kioh Gyoku''. Getting hit by projectiles or enemies will lower the shield percentage; if it reaches 0, the shield will break, leaving your character vulnerable. If your character is hit while shields are down, they lose. Shields will slowly recharge as long as the character isn't hit, even if they're down. Also featured prominently on the player craft in ''Samidare''.
* DirtyOldMan: The omake all but outright states that VIVIT's design is relevant to Erich's interests.
* {{Early Bird Cameo}}/{{Older Than They Think}}: In the extra stage of the first game, Reimu and Marisa use their Windows designs. The game predates ''Embodiment of Scarlet Devil''.
* {{Expy}}: Hirano, with ''Franchise/TouhouProject'''s Reimu Hakurei.
* FightingYourFriend: In stage 4 of ''Banshiryuu'', you will fight against the character you didn't pick.
* FragileSpeedster: Mei and Mai in Kioh Gyoku are very fast, but they have the lowest defense in the game.
* TheFuture
* GenreShift: ''Kioh Gyoku'' is a two-player versus shooter, much like the ''Franchise/TouhouProject'' ''Phantasmagoria'' games.
* GreenRocks: Saboten energy.
* HaveIMentionedIAmHeterosexualToday: One of Morgan's win quotes against Marie in Kioh Gyoku mentions that she's straight.
* HitboxDissonance: Intentional, and highly encouraged, in the case of ''Kioh Gyoku''.
* HumongousMecha / PoweredArmor: Erich is fond of piloting these. They're known as the Hi-Beion line.
* ImprobableAge: Mei and Mai are 6 year old soldiers, Yuuta Kirishima can't be older than 15, and Marie is a retired legendary soldier at 18.
* ImprobablyFemaleCast: Averted, unlike its sibling series. Although the cast is still mostly female, male characters are featured in the games (and even playable, in the case of ''Kioh Gyoku''.)
* LipstickLesbian: Marie's a prime example of this, due to her feminine looks and personality.
* MacrossMissileMassacre: One of VIVIT's shot-types in ''Shuusou Gyoku''. Also a favorite tactic of Marie's.
* MightyGlacier: Marie has very high attack and defense in Kioh Gyoku and is the slowest character as well.
* {{Miko}}: Hirano Sakurasaki works as a shrine maiden.
* MissionControl: Erich, for VIVIT. Gyoku, for Hirano.
* NintendoHard: All three games to an extent, but ESPECIALLY Banshiryuu.
* NonstandardGameOver: ''Banshiryuu'''s Stage 2 boss, [[spoiler: Yuuta Kirishima]] brings in an "Earth Destruction Bomb" during his last pattern. Shooting it enough will cause it to explode, resulting in an instant GameOver, regardless of how many lives or continues the player had remaining.
%%* OneWingedAngel: The FinalBoss of ''Shuusou Gyoku'' has three forms.
%%* PowerUpMagnet
* PowerGivesYouWings : Marisa sports a pair of wings for her cameo appearance - She is more powerful here than pretty much any other appearance. The FinalBoss of ''Shuusou Gyoku'' also has angel wings.
** Yuuka also gets wings for her cameo appearance.
* RecurringBoss: Gates and VIVIT (if you include all versions of her) are the only characters who are featured as an opponent in every Seihou game, including Samidare.
* ScienceFantasy: {{In a world}} of ScienceFiction, there's Muse, a vampire alchemist who wants to [[{{Magitek}} combine magic and technology,]] and Yuitia, a ghost with tremendous power. Saboten energy also appears to have almost fantastical properties, if what happened to [[spoiler: Erich's daughter Vivit is any indication.]] The protagonists are a shrine maiden and a robot girl, and the cameos feature a shrine maiden, a witch and a flower youkai.
* ScrewYourself: Marie makes hints at this trope in one of her Kioh Gyoku victory lines.
->''"So, my fake self... Let's do something... wonderful."''
-->--'''Marie''', ''Kioh Gyoku (when winning against herself)''
* ShoutOut: Stage 4 of ''Banshiryuu'' is an extended ''Franchise/TouhouProject'' ShoutOut based primarily on stage 4 of ''Lotus Land Story''. It changes depending on who you're playing as like stage 4 of ''Lotus Land Story'' (and later ''Imperishable Night''). If you're playing as VIVIT, you'll face the doofy ghosts that were common in the PC-98 games before facing off against a miko that throws aroung yin-yang orbs, like Reimu. Hirano goes through a stage quite similar to the original stage 4 of ''Lotus Land Story'', before fighting VIVIT, who's already existing association with stars and lasers is ramped up, and she starts riding a broom just in case you missed that she's being Marisa.
* SpiritualSuccessor: Samidare is regarded as one, though Shunsatsu Sare Do's next game, [[https://ss-do.sakura.ne.jp/#/games/smml SUPER MATE MATE LASER]], is an official one, using many of the same resources as ''Banshiryuu''.
* StalkerWithACrush: Marie, towards VIVIT.
->''"Yes, yes, Marie. She's such a sadistic person indeed. Since then, she asked me out on a date 4 times..."''
-->-- '''VIVIT''',''Shuusou Gyoku Ending''
* SuperMovePortraitAttack: Boss attacks in ''Kioh Gyoku'' and the SE attacks used by bosses in ''Banshiryuu''. Averted in the case of actual Bombs, with the exception of wide shot type VIVIT's bomb from Shuusou Gyoku, which does display a portrait.
* SuspiciouslySimilarSubstitute: In ''Banshiryuu'', the character VIVIT-r is different from the original VIVIT protagonist from the first two games. VIVIT however appears in ''Samidare''.
* ThemeNaming: The title for each game is named after a cactus.
* {{Tsundere}}: Hirano. [[InformedAttribute Supposedly.]]
* UpdatedRerelease: The C74 version of ''Banshiryuu'', which features a revamped layout, bullet patterns, new music, altered game mechanices, and the long-awaited BossRush BonusLevelOfHell.
* WithGreatPowerComesGreatInsanity: [[spoiler: (Human) Vivit and Yuitia.]]
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