When Haruma Kawagoe was a boy his mother had a miscarriage; and to make up for it, Haruma asked Santa for a little sister at Christmas. Now, years later, Haruma is a college student living away from home. His slumber is disturbed one night by the faint sound of… Santa on a flying motorcycle?! She has come to deliver a present that has taken many years to make: a little sister of his own, a little girl he names Choco. The two of them begin to live together but Choco has a lot to learn, and all of her life skills must come from what her brother tells her and her instruction manual. Choco's life is her brother, but as time goes by she gradually learns to become her own person.
Ten-year-old genius Chiyo, animal-loving Sakaki, loudmouth Tomo, athletic Kagura, weight-conscious Yomi and dim-witted Osaka are six friends who share laughs, good times, and a high school homeroom. With scary (and sometimes perverted) teachers, school festivals, penguin suits and general hilarity abounding, you can be sure that there's never a dull day in the life of one of these students!
While Chokotto Sister has it's own drama within the story it and Azumanga are similar in providing good humor and the 'main' characters share traits that are sure to be obvious if you watch. Both are enjoyable and very relaxing and calming to watch.
To make money, high school student Shinkurou Kurenai works for the secretive Benika as a "dispute mediator," acting to intervene in the disputes of clients – often violently. One day, Benika gives him a much different assignment: to protect Murasaki Kuhoin, a seven-year-old girl from the wealthy Kuhoin family. This turns out to be a more troublesome task than he expects, as Murasaki is spoiled, naive, and completely unaware of what life is like outside of the luxurious one she had previously. He also has no idea why Murasaki needs his protection, though he is slowly obtaining details from a well-informed classmate. Adding to his problems, Shinkurou still must continue to do his previous work for Benika and take care of his social relationships in school while protecting Murasaki, complicating his entire life. Nonetheless, as time passes, he and Murasaki grow close; however, trouble brews in the shadows as everyone - including Shinkurou - seems to be harboring secrets...
Sawamura Seiji is the most notorious delinquent at his high school -- always getting into fights and causing problems, leaving him single and unlucky with the ladies. After another long day of rejection, Seiji discovers that the love of his life might have finally appeared, but in the unlikeliest of places... his right hand?! Now, in addition to dealing with daily fights and the gossip of his classmates, Seiji must handle a new problem of embarassing proportions: Kasugano Midori, a pretty young girl in place of his hand, who happens to have fallen in love with him!
In both series, a guy is living alone when, suddenly and involuntarily, a girl who idolizes him is thrust into his life. The primary difference is that Seiji has to keep Midori a secret, and Haruma only has to keep secret Choco's origin.
Additionally, both series are a bit ecchi. Differences: Chocotto Sister has more ecchi, but self-censors any body parts, while Midori no Hibi goes as far as bare breasts, but less often.
Midori and Choco also both keep a diary/journal sort of thing to develop their characters more.
When Daikichi's grandfather dies he leaves behind a young daughter named Rin. However, as most of the family is embarrassed at the idea of a 79-year-old man having a six-year-old child, they can't seem to figure out what to do with her. Disgusted by this behavior, Daikichi decides to take care of her himself, but he's a bachelor, has no idea how to raise a child, and isn't even all that comfortable with kids! Now, Daikichi must do the normal things a parent does such as enroll her in school, buy her clothing and teach her about the life and world around her. But more importantly, he must also help her deal with her father's death and decide whether or not she should try to find her mother. Together, the two begin their unlikely relationship as father and daughter, navigating each of life's bumps along the way.
In both shows you will find an adorable girl suddenly under the care of a male protagonist. They each have their great share of cute scenes, comedy, and a pretty bland storyline that doesn't really go anywhere except daily life of the two. But they are both a fun watch on very similar terms.