Bunny Drop

"Don't you think this world is better than you expected?"

"One bright autumn day, I learned of Grandpa's demise. Hence I took a leave of absence, packed my bag, and rushed home. Only to find a little girl I had never seen before."

When Daikichi Kawachi questions his mother, he learns that the six-year-old girl is Rin, his grandfather's illegitimate daughter. When everybody else in the family makes excuses to avoid taking care of her, Daikichi gets pissed off and impulsively takes her in himself. From buying her clothes, getting her into kindergarten, transferring to a job with better hours, and trying to work out what to do regarding Rin's absentee mother Masako, Daikichi does all in his power to do right by Rin, no matter the cost to himself.

Bunny Drop (Usagi Drop in Japanese) is a Josei manga by Yumi Unita centering on the drama of bachelor Daikichi and the change he makes to his life so he can care for Rin.

The series is licensed by Yen Press, which was published between 2005 and 2011. An anime (viewable on Crunchyroll) ran on the NoitaminA block in the Summer 2011 Anime, and a live-action movie was released in July of that year.

Tropes used in Bunny Drop include:

Accidental Pervert - Happens to Daikichi early on.
Adult Child - Masako; Daikichi is said to be this in the past, but grows out of it quickly.
- In Daikichi's case, it's pretty obvious early on; while he does have the best of intentions, he's very much out of his depth. While some of it is overboard, there's good reason for his mom to regularly take him to task about child-rearing. In short, while there's no doubt that Daikichi cares and tries to do the right thing, actually getting his act together to do so is a process.
- Masako is a much straighter example. She's described by Daikichi's grandfather as simply not being mature enough to be a mother yet.
All Girls Want Bad Boys: Averted with Kouki. When he goes through his bad-boy phase, it ends up driving Rin away from him.
Art Shift: All of the prologue scenes in the anime are colored pastel-style, in contrast to the more conventional coloring in the rest of the episode.
Bathroom Stall of Overheard Insults - Daikichi overhears some soon-to-be-ex-co-workers accusing him of abandoning them as he's about to enter the bathroom. He opts to just let the matter drop.
Calling the Old Man Out - Daikichi. To his entire family at their treatment of Rin. Both a Crowning Moment of Heartwarming along with a Crowning Moment of Awesome.
Cerebus Syndrome - The story starts out as an innocent, but realistic in terms of character personality, tale about parenting and loving someone else's child. After the timeskip it becomes a story, with teenage Rin dealing with Kouki then about her becoming Daikichi's future wife
Character Development - Every main character gets this, but Daikichi and Rin get special mention.
Children Raise You - Daikichi goes from being an immature manchild to being a responsible and proactive caretaker, with a few missteps along the way. He even lampshades this at the end of volume 2. Counts as major Character Development.
Continuity Nod - After the Time Skip, Rin still has in her room the desk that they bought when she entered elementary school.
Death Is a Sad Thing - Rin's understanding of Gramps' death, and a fear of her own death that results.
Defrosting Ice Queen: Daikichi's mother wants nothing to do with Rin at first. However, when Daikichi brings her back for a family visit, she begins warming up to the girl to the point where she asks Daikichi and Rin to visit her again.
Elective Mute
Eleven Episode Anime
Emotionless Girl - Deconstructed: Rin acts like this around people she's afraid of or doesn't trust (most everyone to begin with), and some of Daikichi's relatives cite it as a reason why they won't take her in. We soon find out that Rin is anything but.
Evolving Credits - in the anime, the ending sequence changes slightly to match the content of the episode during the first section and also in the colored pencil/chalk pastel drawing of Rin towards the end
Face Palm - Please note: asking a little girl to keep a secret will have unexpected results.
First Girl Wins - Rin ends up marrying Daikichi
Funny Background Event: A few in the anime, one of them involves Rin playing on her new futon while Daikichi is on the phone
Harsh Word Impact
Happily Adopted
Hot Dad - The father of Sayaka (a classmate of Rin's), who is a former model. Remarked upon in-universe.
Hot Mom - Ms. Nitani. Played Up to Eleven in the anime.
Identical Grandson - Daikichi looks so much like a young version of his grandfather that some relatives at the grandfather's wake thought Daikichi was a ghost. This is also why Rin initially becomes attached to him.
Idiots Cannot Catch Colds - When Rin gets ill, Daikichi mutters he's lucky he's an idiot.
I'll Never Tell You What I'm Telling You - Rin abruptly starts singing. When asked why, her response is "It's a secret, so I can't tell anyone at home about Parents' Day!"
Imagine Spot - When talking with his parents, Daikichi has frequent Flashbacks to his childhood (often accompanied by the informative caption "Showa-era child rearing!")
Ironic Echo - "This is sweat!"
- "Why not let her use your surname? It'll change anyway once she gets married."
Is That Cute Kid Yours? - Daikichi gets this a couple times. He has no idea initially how to handle it, since "No, she's my aunt" is not something you want to go around saying.
"Ma'am" Shock, male version - Her first morning with Daikichi, Rin calls him "oji-san," which shocks him as much because he's just 30 as because she's his Oba-san in the blood relationship sense. (The official translation obscures the joke by rendering these as "mister" and "ma'am".)
May-December Romance - Daikichi's grandpa and Masako. Rin later on at the end with Daikichi, who is older than her by 24 years.
Meaningful Echo - In the first volume, Daikichi notes that he would be lying if he didn't call raising Rin a sacrifice, but hopes that he can say it in the future. At the end of the fourth (a little over a year after taking Rin in), he says that it's not one.
Meaningful Name - In Japanese, the bellflower is called the rindou. On seeing Rin pick bellflowers for her father's grave, Daikichi realizes his grandfather named her after his favorite flower.
Missing Mom - A plot point is Daikichi learning the identity of Rin's mother and confronting her.
Orphan's Plot Trinket - Rin's baby book. Gives us the first clue about Rin's mother and is the hiding place of Daikichi's grandfather's will.
Noodle Incident: What gave Kouki the scar on his forehead is never fully revealed.
Not Blood Related - Chapter 54 reveals that, Rin isn't Souichi's daughter therefore she isn't Daikichi's aunt.
Not What It Looks Like - When Daikichi gets a visit from his cousin at the same time his Love Interest drops by.
Parental Abandonment - Rin; father dead, mother's whereabouts unknown. Once mother's whereabouts discovered, mother still wants nothing to do with her because she's irresponsible.
Parental Incest - An inversion. Despite being Daikichi's aunt, Rin was raised by Daikichi from childhood and is younger than the former by more than two decades.
Potty Failure - Rin's bedwetting in chapter 4; partly stress, partly scared to enter the bathroom alone at night.
Sand in My Eyes - When Daikichi gets teary-eyed about Rin's feelings for him, he claims it's sweat.
Sink-or-Swim Fatherhood
Shout-Out - Daikichi and Rin do the Algorithm Dance from Pitagora Suicchi.
- "This isn't Dragon Quest!"
Sugar and Ice Personality - Rin is the "Once You Get to Know Her" type, very shy and quiet to anyone she doesn't know.
Time Skip - At the start of volume 5, we skip ten years and Rin is suddenly a teenager. The final chapter is set 2 years after that.
Unlucky Childhood Friend - Kouki, to Rin.
Unresolved Sexual Tension
- Rin and Kouki are at this stage when the post-Time Skip arc begins.
- Further chapters ~~show hints of this~~ beats you over the head with this between Daikichi and Ms. Nitani as well.
- And when the Rin and Kouki thing is resolved, Rin's new love is Daikichi.
Wife Husbandry - As Rin grows up, she develops feelings for Daikichi.