''Dai-Nihonjin'', released internationally as ''Big Man Japan'' is a 2007 Japanese comedy film written and directed by Hitoshi Matsumoto (of the [[Series/GakiNoTsukaiYaArahende Downtown comedy duo]] fame), who also stars as the somewhat-eponymous protagonist. The film utilises a number of styles including {{Mockumentary}}, {{Kaiju}} and mild satire to build its laughs.

The story follows Daisatô, an almost-ordinary middle-aged man, and a documentary being made about his life. Why is such a seemingly non-descript man deserving of the effort? Because he is able to take in great electrical surges to become a gigantic warrior whose purpose is to defend Japan from some truly bizarre monsters, that's why.

Sadly, this inherited superpower is no longer treated with the same public appreciation as it once was. Daisatô's senile grandfather is spending his last days alone in a retirement home, and Daisatô himself has been forced to have his fights televised and judged by the unpleasable populace while he lives alone in a rather decrepit house. He rarely gets to see his daughter and it seems he's a target of green activists and others for the collateral damage he tends to cause. Of course, he doesn't have much of a choice in the matter and by the end of the film, it seems his time has come at the hands of a particularly dangerous monster.

The final product has recieved mixed reactions, but many were at least overjoyed with the surreal comic touch of the film (if not perhaps so with the near [[{{Dramedy}} dramatic elements]]. Fans of Matsumoto's may be able to see recurring themes re-emerging here, as well as being able to see the faces of some of his occasional collaborators.

!!This film provides examples of:
* AffectionateParody / DeconstructiveParody: Matsumoto is an avowed fan of {{Toku}}/{{Kaiju}} movies and shows and the film deconstructs and parody many tropes within the genre.
* AmericaSavesTheDay: [[spoiler: The Super Justice Team ganging up to defeat the devil monster.]]
* ApatheticCitizens: Big Man Japan is destined to protect Japan... but who cares about that when the (''televised'') fights are so boring?
* BadassGrandpa: Daisatô's grandfather turns into a rather odd variant of the trope towards the end.
* BeastWithAHumanFace: Most of the {{Kaiju}} have human faces, yet have varying degrees of intelligence.
* BreatheOnTheFan: Daisatô's grandfather does it, while giant, with an airplane's propeller.
* ChildrenAreInnocent: {{Pixellation}} and voice distortion are necessary in one particularly humourous examination of this trope.
* CombinationAttack: The Super Justice Team invite Big Man Japan to join hands with them in order to fire a beam at a monster he couldn't beat. BMJ moves his hand away briefly and notes that the beam isn't any weaker without him.
* CompanionCube: A cultural example with Daisatô's umbrella.
* CorporateSponsoredSuperhero / ProductPlacement: In-universe, Daisatô is forced to have adverts plastered all over Big Man Japan to gain revenue. He's even told by his agent to be careful when fighting a monster so as ''not to have an advert obstructed''.
* CrouchingMoronHiddenBadass: Daisatô to a degree, though he's really more willfully ignorant because he's TheWoobie.
* CurbStompBattle: Big Man Japan versus [[spoiler: the devil monster]], as well as [[spoiler: said monster versus The Super Justice Team]].
* CursedWithAwesome: Daisatô.
* {{Dramedy}}
* {{Eagleland}}: [[spoiler: The Super Justice Team]] is type 1.
* EvilSmellsBad: One of the monsters.
* EyesDoNotBelongThere: One of the monsters has its one eye in what's otherwise a more... ''private'' area.
* FallenHero: Daisatô/Big Man Japan. One scene uses mock-archive footage from the World War II era to show respected his family (and their ability to fight monsters) once was.
* GainaxEnding: [[spoiler:The CGI animation is replaced with PeopleInRubberSuits, an American superhero family shows up and beats the tar out of the devil monster, and he has dinner with them over the credits. It's supposed to symbolize the decline of Japan's place in the world or something but... What.]]
* HeroWithBadPublicity: Daisatô is inundated with criticism, from insulting graffiti outside his house to a candlelit vigil for one of the monsters.
* HeWhoFightsMonsters / NotSoDifferent: The opinion of just about everyone in Japan when it comes to Big Man Japan.
* {{Kaiju}}: A tribute/[[AffectionateParody par]][[DeconstructiveParody ody]].
* LonersAreFreaks: In a more literal way than normal.
* MagicPants: [[DefiedTrope Defied]]. Big Man Japan's purple pants are really that huge, meaning before growing he has to stand inside them while they're stretched out by tall poles.
* MindScrew: Perhaps unintentionally at times, but [[spoiler: the ending]] takes it to a more comedic extreme.
* {{Mockumentary}}
* OurMonstersAreWeird
** The Strangling Monster: What looks like the unholy offspring between a giraffe and the Michelin Man. It has a comb-over and two arms conjoined by cables, which it uses to squeeze stuff. Also, it [[RefugeInAudacity defecates harpoons]].
** The Leaping Monster: A human head with one reptilian leg. It leaps around yelling "Sei!"
** The Evil Stare Monster: It's best described as a headless tarsier with an [[RefugeInAudacity eyeball on its... earthworm penis]].
** The Stink Monster: Actually two monsters. One looks like a mutant jellyfish with a human head. The other is just... creepy.
** The Child Monster: A talking fetus with a full head of hair
* PokemonSpeak: The leaping monster. ''SEI!!!''
* StylisticSuck: [[spoiler: The ending.]]
* ThinkOfTheChildren : Big Man Japan [[spoiler: accidentally kills a baby monster]]. People go apeshit.
** The public's reaction to [[{{Squick}} two monsters mating on TV.]]
* WingedSoulFliesOffAtDeath: Happens after each monster's death. ''In a live-action film.''
* WomenAreWiser: A husband and wife monster duo attack midway through the film. The wife is an lazy but intelligent DeadpanSnarker, the husband an energetic {{Keet}} who does not speak.