History Main / TwelveEpisodeAnime

* ''LightNovel/{{Kampfer}}'' is an odd case; it's 12 episodes, but it's basically an 11-episode series with episode 12 being a fanservicey, non-continuity {{bonus episode}} that's aired after the ending [[GeckoEnding such as it is]].

* ''LightNovel/{{Oreshura}}''

* ''Anime/SailorMoonCrystal'' has ran for three 13-episode seasons, each adapting an arc from the [[Manga/SailorMoon manga]].

* ''LightNovel/{{Kurenai}}''

* ''Literature/{{Bakemonogatari}}'' ran for 15 episodes long.

This format became popular (see [[http://www.google.com/search?q=site%3Aanimenewsnetwork.com+inurl%3A%22encyclopedia%2Fanime.php%22+%22Number+of+episodes%3A+12%22 12]] and [[http://www.google.com/search?q=site%3Aanimenewsnetwork.com+inurl%3A%22encyclopedia%2Fanime.php%22+%22Number+of+episodes%3A+13%22 13]]) in the second half of the 2000s as a compromise to the often sporadic nature of {{OVA}}s and the longer, sometimes {{filler}}-ridden, previous standard of 22-26 (and even earlier, 46-52) episodes. Being a smaller time investment and financial risk, it is much easier to determine if a show will be successful; or, if it isn't, to not take on as much of a loss. In that respect, the closest Western equivalent to this trope would be Front13Back9.

This format became popular (see [[http://www.google.com/search?q=site%3Aanimenewsnetwork.com+inurl%3A%22encyclopedia%2Fanime.php%22+%22Number+of+episodes%3A+12%22 12]] and [[http://www.google.com/search?q=site%3Aanimenewsnetwork.com+inurl%3A%22encyclopedia%2Fanime.php%22+%22Number+of+episodes%3A+13%22 13]]) in the second half of the 2000s as a compromise to the often sporadic nature of {{OVA}}s and the longer, sometimes {{filler}}-ridden, previous standard of 22-26 (and even earlier, 48-52) episodes. Being a smaller time investment and financial risk, it is much easier to determine if a show will be successful; or, if it isn't, to not take on as much of a loss. In that respect, the closest Western equivalent to this trope would be Front13Back9.

* ''LightNovel/{{Oresuki}}'' received a 12-episode anime adaptation covering the first 4 volumes of the light novel series, with an OVA release the following year (one that was postponed by the COVID-19 pandemic) to adapt the fifth volume.

* ''LightNovel/GirlishNumber''

* ''LightNovel/GrimgarOfFantasyAndAsh''

* ''LightNovel/MayoiNekoOverrun'' has twelve episodes plus a {{metafiction}}al thirteenth episode of the characters doing commentary on the series.

* ''LightNovel/HeavensMemoPad''

* ''Anime/GonnaBeTheTwinTail''

* ''LightNovel/GroundControlToPsychoelectricGirl''

* ''LightNovel/{{MM}}''

* ''LightNovel/{{Oreimo}}'' has twelve broadcast episodes in its first season and 13 in its second, plus four {{OVA}} episodes.

* ''Anime/PantyAndStockingWithGarterbelt'', though Creator/StudioGainax apparently has a second season planned, although it's very unlikely to happen as the series creator left Gainax to create Creator/StudioTrigger.

* ''Literature/RavenOfTheInnerPalace''

* ''Manga/SpyXFamily''[='=]s first season is 25 episodes but aired in two parts, 12 episodes from April to June 2022 and the next 13 starting in October.

* ''LightNovel/HowToRaiseABoringGirlfriend'' plus an OVA episode.

* ''LightNovel/TheFamiliarOfZero'' started with 13 episodes, and has three sequel seasons with 12 each.

* ''LightNovel/IsThisAZombie'' had 12 episodes in its first season, but its second season had only 10 episodes.

* ''LightNovel/InfiniteStratos'' has two 12-episode seasons, not counting the OVA.

* ''LightNovel/TheMisfitOfDemonKingAcademy''

* ''Anime/MyTeenRomanticComedySNAFU'' and its sequel have 13 episodes, each season also have an OVA episode.

* ''LightNovel/KokoroConnect'' has 13 episodes, but with 4 [=OVAs=] on the way in 2013, it's an amount of 17 episodes altogether.

* ''Manga/RecoveryOfAnMMOJunkie'' (plus 2 [=OVAs=]).

* While ''Literature/BeyondTheBoundary'' only has one 12-episode season in 2013 with a prequel OVA, it later received two movies, the first one aired in 2014, adapting the anime series; the second one served as a sequel, which aired in 2015. It also had several spinoff shorts.

* ''Manga/TheWorldGodOnlyKnows'' had three seasons that are 12 episodes long each (plus 4 OVAs).

* ''Manga/TheWorldGodOnlyKnows'' had three seasons that are 12 episodes long each.

* ''Webcomic/MobPsycho100'' started with a 12-episode first season, then got a second season of 13.

* ''Manga/BlackBloodBrothers''

* ''LightNovel/OutburstDreamerBoys'': Plus one OVA.

* ''LightNovel/AndYouThoughtThereIsNeverAGirlOnline''

* ''LightNovel/TheHeroIsOverpoweredButOverlyCautious''

* ''Anime/IronMan''

* ''LightNovel/{{Katanagatari}}'' has twelve episodes, but each episode is fifty minutes long and was aired monthly rather than weekly.

* ''LightNovel/KureNai''

* ''Anime/{{Wolverine}}''

* ''LightNovel/{{No6}}''

* ''[[LightNovel/MyMentalChoicesAre My Mental Choices Are Completely Interfering with My School Romantic Comedy]]''

* ''Literature/{{Haganai}}'' started with 12 episodes in fall 2011, then got another 12-episode season in winter 2013.

* ''LightNovel/LoveChunibyoAndOtherDelusions''. Both seasons contain 12 episodes plus an {{OVA}}. Given their plot importance, they could be seen as 13-ep seasons.[[note]]This also doesn't include the six per season ''Lite'' episodes which together equal another complete episode.[[/note]]

* ''LightNovel/{{Bakemonogatari}}'' ran for 15 episodes long.

* ''LightNovel/FateZero'''s first season has 13 episodes, but it's effectively 14 episodes, because the first episode is 45 minutes long. This was apparently done to get the [[InfoDump humongous amount of prologue exposition]] (for a show which is ''itself'' a prologue for [[VisualNovel/FateStayNight an entire franchise]]) out of the way in the first episode. The second season is a normal 12-episode season.

* ''LightNovel/DragonCrisis''

* ''LightNovel/CubeXCursedXCurious''

* ''LightNovel/CoffinPrincessChaika'': 12 episodes for season 1, 10 for season 2.

* While ''LightNovel/BeyondTheBoundary'' only has one 12-episode season in 2013 with a prequel OVA, it later received two movies, the first one aired in 2014, adapting the anime series; the second one served as a sequel, which aired in 2015. It also had several spinoff shorts.

* ''LightNovel/IsItWrongToTryToPickUpGirlsInADungeon'' with an OVA episode.

* The 2019 adaptation of the ''LightNovel/BoogiepopSeries'' was 18 episodes long. The series started off with a one-hour special with the first two episodes debuting immediately, and then in a truly unique situation, episodes 10-13 were all released at once when the show hit that point, leaving enough time for the entire season to finish its run in a standard season.

* ''LightNovel/{{Durarara}}'' in its initial run had 24 episodes, divided into two halves and denoted by the different opening and closing credits sequences. For its second run, it had 36 episodes which were divided into three cours. Unlike the first run where both cours were broadcast back-to-back, the new cours were released separately - ''Shou'' was in Winter 2015, ''Ten'' was in Summer 2015, ''Ketsu'' was in Winter 2016.