->''Then I was a brand-spanking new freshman university student and countless doors to the mystical treasure that is known as that 'rose-colored campus life' lay open before me. I was half-swooned with glee. And the one I chose was...!''

''Yojo-han Shinwa Taikei'' (''A Compendium of 4.5 Tatami Mythology'') is a 2004 novel by Tomihiko Morimi, narrated by an [[NoNameGiven unnamed]] third-year agriculture student at Kyoto University. After getting dumped by a crush his first year, he's become convinced the idealised, lovey-dovey campus life he expected will never become reality, and as a result, has wasted the last two years ruining the love lives of others at every opportunity with his partner in crime, Ozu. Despite this, the narrator has taken a liking to Akashi, a girl one year his junior.

One late night while eating ramen at a cart near his boarding house, our narrator meets a man claiming to be a god of matrimony. The god tells the protagonist that come the tenth lunar month, the gods will gather in Izumo and determine who will marry whom--and Akashi's hand is either going to him or Ozu. When a fortune teller further tells him he's at a crossroads--one path leading to a life of happiness, [[GroundhogDayLoop the other leading to one of the same frustration and monotony he's currently experiencing]]--the narrator realizes that he needs to get a move on.

The novel was adapted to anime for Creator/NoitaminA's spring 2010 season, directed by Creator/MasaakiYuasa of ''Anime/{{Kaiba}}'' fame and produced by Creator/{{Madhouse}}. Creator/FUNimation licensed it for a streaming-only, English-subtitled stateside release on the Funimation website, Website/YouTube, and {{Creator/Hulu}} under the MarketBasedTitle ''The Tatami Galaxy''.

!!Exhibits the following tropes:

* AnachronicOrder: Within the first episode.
* AntiHero: The protagonist is a type I, of a very ''Manga/SayonaraZetsubouSensei'' variety without the suicidal tendencies.
* ArcWelding: In episode 9. Episodes 10 and 11 also spell out most of the consistent factors of the setting across each timeline.
* ArmorPiercingSlap: Akashi can pull these off (and does so, several times).
* ArtShift
* BeautyMark: Akashi and Hanuki both have one.
* BeehiveBarrier: [[http://celestialkitsune.files.wordpress.com/2010/05/tatami-galaxy_00090.jpg Akashi can erect one.]] Figuratively, of course.
* BigGood: Higuchi, who [[spoiler: tries to get [[NoNameGiven Watashi]] to drop his dreams of a rose colored campus life and ''live'']].
* BreakingTheFourthWall: Since the narrator doesn't seem to be aware of the time loop, his references to the fortune teller's prices increasing and their conversation getting shorter each time probably qualify as this.
* BrickJoke: There are several--for example, the situations the narrator imagines before picking a club every episode eventually all come to pass; in another example, the proxy war first explained in episode 4 [[http://static.tvtropes.org/pmwiki/pub/images/02_Movie_Circle_Misogi_mkv_snapshot_05_35_2010_05_18_18_35_56_3338.jpg appears in episode 2 as a student film of the narrator's.]]
** Episode 7 has the narrator use a metaphor about wandering a maze of 4.5 tatami rooms, which is the literal subject of one of his other student films in episode 2. [[spoiler:In episodes 10 and 11, the narrator actually does this.]]
** Episode 5 has a random man suddenly stumble into the room. The protagonist understandably freaks out. [[spoiler:It's the protagonist from episode 10 and 11, where he's wandering the maze of 4.5 tatami rooms.]]
** And in episode 4, he finds a bag of money in his room, which he assumes was planted there so he could pay for the [[MacGuffin turtle scrub-brush]]. [[spoiler:In episode 10, we learn that it was ''his own'' money, which he amassed by stealing some cash from each alternate universe tatami room.]]
%%* BromanticFoil: Ozu.
* CannotSpitItOut: The narrator can't return Akashi's Mochiguma and he can't ask her out to Neko Ramen, [[spoiler:at least until the finale]].
* CargoShip: [[spoiler:Jogasaki is in love with a mannequin he named Kaori. In one timeline, the narrator falls in love with it as well.]] [[invoked]]
* CharacterDevelopment: [[spoiler:By the finale, Ozu and the narrator have basically switched places, but definitely not in a bad way.]]
* CherryBlossoms
* ChurchOfHappyology: [[spoiler:Honwaka]].
* CicadianRhythm
* ClockTower: It shows that time is rewinding, causing the protagonist to live his college life again each episode.
* CloudCuckooLander: Pretty much everyone has elements of this, but particularly Higuchi.
* ColorCodedForYourConvenience: The major characters have their own color motifs, presented in the opening and occasionally in the show (the Protagonist has white/light grey, Akashi has light blue, Ozu has red, Jougasaki has orange, Hanuki has pink/red, and so on). Each episode tends to have its own set color as well. [[spoiler: The episode color schemes become a piece of very subtle {{foreshadowing}} in later episodes.]]
* ContinuityCavalcade: Everything from the past episodes come back one way or another in episodes 10 and 11.
* ADateWithRosiePalms: Implied in a couple of instances in the episodes dealing with the protagonist's romantic pursuits. His sexual desire is represented by a sort of phallic-looking cowboy named Johnny, and in some instances, Johnny is shown kept at bay in a hamster wheel with a [[PornStash girly mag]] and Kleenex box close by.
* DerangedAnimation: It's a Yuasa anime, isn't it? It's positively tame compared to his other works, however.
* DesperatelyLookingForAPurposeInLife: The protagonist's being so swept up in finding a rose-colored college life is what, ironically, blinds him to how meaningful his experiences really are.
* DoesThisRemindYouOfAnything: The tower in episode 6. Especially when it's aligned suspiciously with [[LoveableSexManiac Jogasaki]].
* DrinkingContest: One between Jogasaki and the protagonist in episode 6. [[HardDrinkingPartyGirl Hanuki]] joins in later. [[spoiler:The protagonist wins, although it really seems that Hanuki did.]]
* EarnYourHappyEnding: [[spoiler:After all the rewinds, troubles, and lessons learned, the protagonist has lost all the closeness he had with the other characters--but at least he knows to appreciate all of them more. And even better, he finally summons up the confidence to ask Akashi out to that bowl of neko ramen.]]
* EpiphanicPrison: [[spoiler: The titular galaxy is revealed to be one.]]
* {{Expy}}: The narrator has a certain resemblance to one [[Manga/SayonaraZetsubouSensei Mr. Despair]].
* EyeBeams: Akashi can also (figuratively) fire these.
* FirstEpisodeSpoiler: The series seems like it might be an ordinary, albeit fast-paced SliceOfLife at first... then the episode ends on the note of the protagonist blaming the club for his failures in achieving his [[ArcWords rose-tinted college life]] and [[ResetButton time being thrown back]], setting up for [[GroundhogDayLoop the rest of the series]].
%%* FirstGirlWins
* FoodPorn: Neko Ramen.
* ForeverWar: No one remembers how the [[spoiler:Masochistic Proxy Proxy War]] started.
* FortuneTeller: Appears in each episode, always giving the protagonist the same advice. [[RunningGag And increasing her fee by 1000 yen each time.]]
* GilliganCut: In episode 8 features one.
--> '''Watashi''': Out of the question! Visiting the home of your pen-pal is completely unacceptable! That's breaking the most fundamental rule! I absolutely will not!
-->''*next shot cuts to him standing in front of his pen-pal's home*''
* GoodAllAlong: [[spoiler: Ozu is still kind of a jerk, but the main character eventually realizes why he does the things he does and that, deep down, Ozu was his best and only real friend.]]
* {{Gonk}}: Ozu. The narrator even compares him to a ''{{youkai}}'' several times. However, the opening and episode 7 hint toward this being more than it seems, and the finale makes it clear that [[spoiler:his bizarre appearance was simply a reflection of the narrator's opinion of him. The protagonist later adopts Ozu's usual look to illustrate their switched roles.]]
* GreyAndGreyMorality: Absolutely every main character has done some good things and some questionable ones. It is all about perspective, and we discover that both the good and the bad stuff are who they are. In fact, [[spoiler:that is [[AnAesop kind of the point.]]]]
* GroundhogDayLoop: Although it seems the narrator isn't ''totally'' aware of it and will be joining a different club every time. Besides, it's directed by Yuasa. There had to be ''something'' {{Mind Screw}}y about this show.
** The narrator eventually becomes aware of the repeats in Episode 10 after [[spoiler:busting through the various tatami rooms of each of the alternate universes]]
** It becomes apparent that [[spoiler: Akashi is the only girl for the narrator (episodes examining him in pursuit of other girls have all ended in miserable failure) and the fortune teller has said again and again (in so many words) that returning her Mochiguman charm and hooking up with her is the only way he'll be happy. The narrator himself has also come to take Ozu as more and more of a threat to all of this.]]
* HardDrinkingPartyGirl: Hanuki.
* {{Hikikomori}}: In episode 10, the Narrator has become so fed up with the GroundhogDayLoop (even if he's only subconsciously aware of it) that he decides to spend as much time as possible in his 4.5 tatami room. [[spoiler: Of course, as he starts traveling across the various iterations of his college life, he starts to realize how much he missed out on by abandoning any chance of meeting the cast of characters that had defined his college life in the other iterations.]]
* HomoeroticSubtext:
** Ozu rubs up against the narrator when they're about to sabotage a romantic night for several couples with fireworks from across a riverbank.
---> "But it's so cold..."
** Happens again in episode 5... only this time it happens at night, under the covers, on a boat on which the two of them are escaping down the river. Oh, and Ozu is dressed as a woman.
** In episode 2, they kiss in a movie. [[spoiler: And knowing all the films filmed are in fact other reallities, this could be another one we don't finally see!.]]
** Ozu claims that he and the narrator are connected by a "black string of fate" -- a nod to the traditional {{red string of fate}}.
** "It's my way of expressing my love!"
* HumiliationConga: In episode 2 the narrator and Ozu replace Jogasaki's Alexander the Great movie with a series of clips demonstrating that Jogasaki is [[FullSpectrumMorality not exactly perfect.]]
* IdiosyncraticEpisodeNaming: Every episode is named after the text on the flyer of the club the narrator is a member of in that episode.
* JigsawPuzzlePlot: The narrator does different things each loop but because of this we learn more on the other characters who more or less do the same things each time. Things like [[spoiler:Ozu having a girlfriend, the proxy war, the narrator's three love interests, the clubs Ozu joins]] and other things that happened in previous loops still happened if not mentioned.
* KickTheDog: Ozu is actually sort of likeable in episode 1 and even seems to be trying to set up the narrator with Akashi. As the series goes on Ozu gets progressively more morally ambiguous until he starts to seem like little more than a sinister criminal, until [[spoiler:in the last episodes the narrator discovers the reasons behind Ozu's actions and re-examines his relationship with him and realizes that he is his only friend]].
%%* {{Kuudere}}: Akashi.
%%* LargeHam:
%%** The protagonist.
%%** Ozu and Jougasaki.
%%** Johnny.
%%* LoveableSexManiac: Jogasaki and, arguably, [[spoiler: the protagonist.]]
* MacabreMothMotif
* ManipulativeEditing: The [[HumiliationConga Jogasaki "biopic"]] Ozu puts together.
* MarketBasedTitle: As the original Japanese name translates to ''A Compendium of 4.5 Tatami Mythology'' or ''The Four-and-a-Half Tatami Mythological Chronicles'', it's no wonder they marketed it in America as ''The Tatami Galaxy''. The original title is a mouthful, the 4.5 part (which refers to the size of the narrator's room) would be lost on American viewers.
* MeaningfulName: Ozu's name is pronounced the same way as a Japanese word for "fearful". Same with Akashi ("evidence" or "testimony") and Hanuki ("tooth extraction", appropriate for someone who works at a dental practice).
* MediumBlending: Most obviously in the last two episodes, where 2D animation mixes with real life.
* MindScrew: Copiously, but especially when the matchmaking god finally finishes reading ''Literature/TwentyThousandLeaguesUnderTheSea'' and reaches Nirvana.
* MobileKiosk: The elusive but very good "Neko Ramen" stand where the narrator meets the matchmaking god. Akashi wants to eat there but has never found it.
* MotorMouth: Everyone indulges in it a bit, but the narration in particular can get a bit ridiculous.
* NakedFirstImpression: [[spoiler:Pretty much everyone towards the protagonist, in the finale. Ozu's the only one to find it odd.]]
* NoNameGiven: The narrator is never named but is referred to as "I" or "Myself" in the credits and other materials. Ozu's and Akashi's given names are also never mentioned.
* NotWhatItLooksLike: The narrator gets manipulated into looking like he's [[strike:confiscating]] stealing the Birdman team's plane. Of course, Akashi just happens to arrive and comes to the wrong conclusion. [[spoiler:In a later episode, he is the one who stole the glider in that incident.]]
* OnceAnEpisode: The narrator will deliver the page quote verbatim right after the opening plays, and later on he'll run into the fortune teller, who will have hiked her fee up another thousand yen. At the end of the episode, the university clock tower will appear and run backwards and blur into the series logo as the credits start.
** The fortune teller bit is double-subverted in episode 8, where she initially only charges 6000 yen, but later on addends to the narrator's fortune and charges him another 2000.
** [[spoiler:Although later the standard clock tower ending is missing from episodes 9 to 11]].
** Every time the narrator meets Ozu for the first time (sic; no, really!), Ozu delivers a speech explaining that they really are comrades. [[spoiler:This is reversed in the last episode.]]
* OutOfClothesExperience: [[spoiler:Subverted in the finale; the narrator symbolically goes through several outfits matching other lives as he dashes to save Ozu, which makes the fact that he ends up nude at the end of it seem like a mental thing, but nope, he actually ''is'' nude in public.]]
* PuttingOnTheReich: Jogasaki is compared to a [[DoesThisRemindYouOfAnything charismatic dictator]], and there are scenes that depict him in appropriate dress along with his club members in uniform and goose-stepping.
* SaveScumming: You could call the whole concept this, but the trope fits episodes 6-8 especially well, where the narrator rewinds his life only by a few hours so he can try every path in a situation where three girls want him at once.
* RedStringOfFate:
** Ozu claims he and the narrator are linked by a ''black'' string of fate. This is usually accompanied by a visual of the two tied up together in black cord and sinking into the Mariana trench.
** In a more straight example of this trope, Akashi and the Narrator seem to be tied by the RedStringOfFate. He simply cannot be happy without her, and Akashi's behavior seems to demonstrate that she likes him too.
* TheReveal: In episode 9. [[spoiler:Ozu's got a girlfriend -- who is incidentally ''Honwaka's daughter'' -- and has been doing all these questionably moral things for two years for the sake of the perfect date with her.]]
* ScaryShinyGlasses: The narrator at times.
* ShaggyDogStory: Every episode [[spoiler:except the last one]].
* ShippingBedDeath: In-universe. [[spoiler:The narrator [[LampshadeHanging lampshades]] this as justification in the finale to wrap up other loose ends as opposed to expounding on the details of his budding relationship with Akashi.]]
* ShootTheShaggyDog: The third episode.
* SliceOfLife: Outside of the GroundhogDayLoop, this can very much be considered a ShaggyDogStory version of this.
* SpoilerOpening: Although you may not realize it at first. [[spoiler: The opening contains scenes of someone moving through several rooms that are all the same, save for their different colors. This spoils the protagonist being trapped in the 4.5 tatami world and discovering all his alternate lives with the differently colored rooms.]]
** Someone with a quick eye will also notice [[spoiler: human-looking Ozu toward the end of the opening. This spoils the Protagonist's unreliable storytelling.]]
* TheStoic: Akashi, but she has her moments.
* SuspiciouslySpecificDenial: From episode 6:
--> '''Narrator''': That's just a hobby! It's not like I'm trying to add some extra flavor to my campus life or something!
* TitleDrop: While not formal, the last two episodes reveal why the American title has "Galaxy." In that [[spoiler: the narrator travels (literally) through each alternate version of his room (which is sized at 4.5 tatami).]]
* ToxicFriendInfluence: Ozu, in the eyes of the narrator. [[spoiler: And vice versa.]]
* TricksterArchetype: Ozu. Depending on your point of view, he's also a TricksterMentor... though what he has to teach isn't always good.
* [[UnreadablyFastText Unreadably Fast Subtitles]]: The natural consequence of the narrator's MotorMouth.
* UnreliableNarrator: Despite his protests, he really does seem to have some feelings for Akashi, even before his eventual (and too late) revelation. Also, even though Ozu has [[ManipulativeBastard taken advantage of the Narrator many times,]] it doesn't seem to have occurred to the Narrator that Ozu has actually been looking out for him and has helped him on several occasions. Also, [[spoiler:Ozu's {{Gonk}} is only due to this trope.]]
** [[spoiler: The fortune teller's {{Gonk}} is similarly related to the protagonist's interpretation of her as being a "witch" of sorts - she is later seen with a normal nose and no longer radiating that "powerful aura."]]
* UnusualEuphemism: The narrator's "Johnny," which is visually represented by a silly-looking cartoon cowboy.
* VillainProtagonist: [[spoiler:The narrator goes through a rather bad phase in episode 9]].
* VitriolicBestBuds: The narrator and Ozu, the former supplying the vitriol. The narrator is also very quick to point out the reasons Ozu is a terrible guy in the narration.
* VomitDiscretionShot: Hanuki in episode 10.
* WhyDidItHaveToBeSnakes: Akashi is terrified of moths; a moth landing on her face and the aftermath demonstrate the only {{moe}} chink in her [[TheStoic poker face]].
* WineIsClassy: In the romance-geared episodes, as the protagonist tries to present himself as suave and worldly, several scenes show him as better looking than in reality and lounging in a fashionable apartment (also not the reality) with a glass of wine in hand.
* {{Youkai}}: Ozu is compared to one in episode 1 and even grows a kitsune tail several times in episode 2.