->''"Hey, did you know? Normal humans can't use more than 30% of their brains. But some humans called "Clowns" can use a special magic that allows them to use up to 50 or 60% of it. However, in compensation, they have to respect a certain "condition" linked to this power. Should they violate this condition… they would lose "something precious" within them."''

When the young girl Mana Hinoki arrives in Toykyo, capital of Japon (there are no typos), she stumbles across a young boy named Showtaro and quickly discovers that he is a "Clown": a human who awakened a special power, but has to stick to a specific condition. Showtaro can use the powers of various animals by biting one of their bones, but in exchange has to accomplish at least a good deed every day. After a little incident, Mana accepts to help Showtaro in his search for his best friend Emine. They are soon joined by Yowhey Nanami, a genius inventor who is chased by the Fear Factory, an evil firm for which he build a (defectuous) [[HumongousMecha giant robot]].

Published between 2002 and 2003, ''B.Ichi'' is the first, not so successful manga of Atsushi Ookubo. You could say ''B.Ichi'' was to him what ''Manga/ZombiePowder'' was to Creator/TiteKubo. After Ookubo went and wrote ''Manga/SoulEater'', a much longer and much more successful series, this one fell into oblivion and is almost unknown even in Japan, but you could already find a few of the recurring graphic motifs of ''Soul Eater'' (like the skull). The series's characters, technology and environments have a rather peculiar design, and it doesn't take itself too seriously most of the time. The arstyle is also quite different from the one the author would adopt in his next work.

!!Tropes featured include:
* AbortedArc: All this talk in chapter 2 about "4 powers needed to fight the darkness"? Yeah, it's never mentionned again. Also, the entire Gathering of the Masks arc was aborted due to the series being cancelled.
* ArtEvolution: Not striking since the series is only 20 chapters long, but the faces are noticeably more rounded in the late chapters.
* BigBad: The Hakutaku… sort of. Considering Emine is forced to be the bad guy because of it.
* BookEnds: The very first color page is [[spoiler:Showtaro]] sitting on a crooked branch, holding a giant bone, with a graveyard-like landscape in the background. This is also the last scene of the series.
* DefenseMechanismSuperpower: Originally at least; Clown powers are dormant within every human, but can awaken when one is mistreated by those around them.
* ExplainingYourPowersToTheEnemy: Usually averted, except with [[spoiler:Lin and Shinoda]] in the fourth volume. [[spoiler:Not that it prevents them from crushing the vice-president effortlessly.]]
* {{Exposition}}: Done more or less subtly in the dialogue, on a regular basis.
* FantasticRacism: The fear and hatred of Clowns is so strong that the governement of Japon has built a unit specifically to eliminate them. In response, a number of Clowns have united under the Clown Alliance to destroy humanity.
* TheGhost: The Fear Factory's president is mentionned only a few times and never appears (he was apparently badly injured when Yowhey's robot slammed itself in the factory's building). The vice-president is the acting BigBad during the Fear Factory arc.
* MegaCorp: The Happy Factory, a giant electrics company; it's real nature is the Fear Factory, a firm specialized in building war weapons.
* MultipleReferencePun: The author himself notes that, while the title refers to the word "bone" (the B) and the concept of "one good deed a day" (the Ichi), you can also separate the word "Bone" to make "B.One", which means the same thing as "B.Ichi". [[LuckyTranslation And according to him, it wasn't even intentional.]]
* NinetyPercentOfYourBrain: The Clowns; although their powers usually don't have anything to do with using more of their brains.
* NoEnding: Due to being CutShort (most likely). The series was probably not planned to be very long since most of the important questions are answered − although vaguely −by volume 4, but the series stops just before what looks like the final battle, and there are still quite a few threads LeftHanging.
* ParentalAbandonment: Showtaro and Emine are both orphans, and it seems Mana was neglected by her parents (it's probably the reason she left home).
* PintSizedPowerhouse: GET, the small robot designed by Yowhey for Mana, can pack enough punch to demolish robots twice its size in the Robot Fight Tournament. Incidentally, Mana herself can qualify.
* {{Pun}}: Tons of them, from various characters, and often untranslatable.
* RedBaron: The most powerful Clowns usually have a nickname. Showtaro is the "Kyōkotsu" (the Mad Skeleton), Emine is the "Hakutaku" (a mythical beast with 8 eyes and a lion-ish body), Nofix is the "Kaiten'ō" (King of Spin), etc.
* ShowWithinAShow: Charisma Justice, the adventures of an invincible and [[LargeHam very hammy]] superhero. Showtaro is a big fan of it.
* TheSmurfettePrinciple: There are exactly 3 female characters, and one of them has only a few pages of screen time. Lin's appearances are pretty scarce too, making Mana the only remotely important female character in the series.
* SpellMyNameWithAnS: Even the Japanase-looking names written in Kanji turn out to have a completely weird spelling, making the orthograph of most of the names dubious.
* StaticCharacter: Almost everyone, including Showtaro, which may be part of what doomed the series' chances of success. The only character who gets any significant development is Yowhey.
* SuperpowerLottery: Not only the powers, but also the conditions can be pretty much anything. It can range from cool ("one good deed a day") to mundane ("regularly bathing in light") to funny ("breathing in a ridiculous way") to thoroughly life-ruining ("one evil deed a day").
* SwissArmyWeapon: Law-Abiding Silver Gun can shoot normal bullets, freezing bullets, be used as a GrapplingHookPistol, or transform into a freaking WaveMotionGun.
* XtremeKoolLetterz: Showtaro and Yowhey's names are prime suspects.