Isshuukan Friends.

These are both romance stories that feature one of the characters with a somewhat difficult social situation. It would be spoilers to explain, but know that in both cases, the female lead has some sort of psychological barrier that must be overcome in order for the romance to proceed properly. Kimi ni Todoke is more blatantly romantic, whereas Isshuukan Friends is more about friendship, as the title suggests. (Still a romance though).  

A boy trying to make friends with a girl who is constantly losing her memories. 

Both Usagi and Issuukan have a soft and light feel along with a little melancholy. If you watched one and would like something that also revolves around daily life (simple things), and two people coming together and interacting, and light soft feel with a little sad then I would recommend these as being similar. The differences: In Usagi the main girl and guy are very different ages and in a guardianship relationship, The story mostly takes place at home. In Isshuukan the story mostly takes at school and the girl and guy are peers. 

The atmosphere in both are very, very similar. The shows live from their character interactions, how the main characters get closer to each other and create bonds. Also, both have a similar art style, very light and calming. While Isshuukan Friends is a little more dramatic, you'll definitely love one if you enjoyed the other. 

main character in both suffer from amnesia and is a romance.  

They give the same relaxing, pleasant vibe. Both are slice of life about getting to know new people and making new friends. Isshuukan Friends has more drama, although it has a lot of funny moments as well; while Tanaka-kun is more about comedy (even the "dramatic parts" are fun). The characters are interesting and cute in both shows. If you watched Isshuukan Friends, I recommend you this, and vice-versa. Enjoy! 

If you enjoy slow-burning romance and slice of life anime featuring shy protagonists, then you'll like these anime. Both have a unique artwork and are very underrated. 

The main heroine in both shows has a secret that makes her avoid other people in order to not get hurt. The male protagonist discovers that secret and decides to be her friend no matter what. Kotoura-san has a darker plot but more comedy and less romance than Isshuukan Friends 

Same atmosphere and animation style. Both series deals with dramatic circumstances in life. 

They have similar premise: a boy who is trying to get close to the heroine The difference is that Tonari no Kaibutsu-kun has more romance portion than Isshuukan Friends that just about friendship story. 

-Both female main characters can't make friends -Both female main characters have some kind of a (psychological) disability -The male main character helps her to make friends -Same romance vibes -Friendly mothers and good supporting characters 

School relationships, mystery, and romance are central themes in both. The strange occurrence of memory loss or amnesia is present in both as key plot devices, along with characters whose pasts conceal secrets. The way both male protagonists go to great lengths to help the female characters in respective series with so much effort is very similar. Also the way the main female characters in both are alone and are first approached by the male protagonist and helps them to make friends is very similar. 

Memories are important, but sometimes they can disappear without a clue. Plastic Memories and Isshuukan Friends both treat memory loss as a common occurrence, and try to teach the importance of overdosing on memories within a short period of time to create happiness. Both shows also attempt to force feels down your throat. 

Pastel colors and similar romance drama vibes. They both feature very enjoyable romance plots, comedy, drama, and well written and relatable characters. They don't necessarily break new ground, but what they do they do well. If you enjoyed one and are looking for a romance with a similar feel, try the other.  

Boy trying to become friends with a cold, distant girl who in actuality really wants to make friends.  

the both have a cute high school romance in common. Both female leads are quiet and have struggles socializing, while both male leads try there best to support and befriend the main female characters. Isshuukan friends can be a bit sadder/ deeper story but both have the soft romcom vibe. 

This is very similar since both of them tells a loving story of lovers realistically and they both have their problems to deal with 

Isshuukan Friends and Jitsu wa Watashi wa both are series of comedy, where the protagonist discovers the secret of a girl, that makes her isolate herself from others. He will become your friend, and will protect your secret, and will support you so that you may one day be well with yourself. In addition there is the risk of their friendship being frustrated, in IF is the amnesia and in Jitsu is that the girl is a vampire. Together they will become closer as they go through the chapters, with the help of their friends. 

They are both about lover trying to be together and they both have there own problem to worry about. In one a a zombie girl that is decaying and in Isshuukan friend it is amnesia on the girl side 

i feel like both is almost the same because both show is all about amnesia..... you guys will understand if you watch either one!!! 

Both series focus on the bond between two friends mixed with the importance of facing obstacles head on. You can find a lot of similar themes with keeping tragic secrets and getting through emotional issues from the past.  

Two protagonists who are friends and feel love for each other. In addition to the art style and the theme of friendship and love. More drama (Isshuukan Friends) and more comedy (Karakai Jouzu on Takagi-san). 

Similar in terms of the premise of memory loss and how the main characters deal with it to maintain their relationships with their friends. Both also have dramatic moments that have the same vibe aside from their wholesome slice-of-life scenes. 

Similar concept of Memory loss but totally Different approach and plot 

-Both have a similar setting -Romance is the main focus in nijiro days unlike isshukan tomodachi -The male and female MCs have a similar vibe -If you're looking for the romance factor in a similar seting to issukan friends then this anime is for you 

Knocking on your door, your destiny may be. Two stories that prove that nothing is impossible, when you strive to achieve it. A girl is unable to make friends because of illness. But a boy will support her at all times so she can share her happiness with others, something she has always wanted. 

-Both anime's themes is about friendship. -Both male leads intentions is to make friends with the female lead. -Both female leads are loners. -Both are about school life. -And after you watched both you'll kinda feel they had the same vibe. 

If you want a comedic type of "isshuukan friends", you should try amagi brilliant park. It has the same idea about the main girl that suffers from "memory problem". the memory of the girl in ABP will reset every one year, while in IF is every one week. not to mention that the story between characters are interesting. enjoy!  

"One Week Friends" / "Isshuukan Friends." and "Hori-san to Miyamura-kun" are quaint slice-of-life short series with some romance dashed in. They both surround a boy and a girl who were formerly strangers slowly getting to know each other well. Both series are relatively light-hearted and share a similar art style, especially in terms of the watercolour-esque background art. Furthermore, much of the character dynamic between the two lead characters of each respective anime with the side characters are also similar. 

The main story of each is about one character's problem and how another attempts to break down the walls that character builds to protect himself/herself. These stories also have important subplots with strong supporting characters. To me the main point of these stories is not so much "romance" as it is the process the various characters go through to make friends, help each other, and discover themselves. 

While not entirely similar by genre standards, Haruhi and Isshuukan Friends gives off a similar vibe with its cast of characters. They both follow a slice of life format although Suzumiya Haruhi no Yuuutsu has the additional element of supernatural element in it. But that element also turns into an arc that shares a similar concept to Isshuukan Friends. Both series tells a story with friends in a lighthearted school life setting where there's any possibility. If you're into stories with a simple yet appealing concept involving memory loss (for Suzumiya Haruhi no Yuutsu, involving a particular arc), give both series a try.  

The theme of reseting is preset in both of these series. In Sakurada Reset, it's more literal time reversal compared to Isshuukan Friends in which only the female lead has her memories reset, but the concept of the female lead losing a part of themselves every week is the same between both series. 

The relationships in Isshuukan Friends reminded me of the ones in Aquarion Evol, although they are in different genres. The prevalence of romance and friendship is a key plot element in both.  

slice of life, similar style, relaxing atmosphere and lonely MC characters Natsume (Male MC) while Issukan (female MC)... In natsume the reason the hero doesn`t have any friends is a supernatural one while in Issukan friends the reason is the heroine's memory loss ....  

The atmosphere in both of them is calm and it focuses on the relationship of two friends who might just be a bit more than only friends... Isshukan Friends has only hints of this however the characters are in the sense that they are sort of clueless when it comes to love.  

In Isshuukan Friends, Hase Yuuki's interaction with Kiryuu Shougo reminds me of the friendship between Tadakuni, Hidenori, and Yoshitake in Danshi Koukousei no Nichijou. The elements of comedy in each series are similar and will make you laugh in almost the same way. Both series have that beautiful slice-of-life feel to them. In fact, both series are listed as Comedy, School, Shounen, and Slice of Life. If you loved one series, you will surely love the other. 

"One Week Friends" / "Isshuukan Friends." and "My Love Story!!" / "Ore Monogatari!!" are cute and sweet shows that involve the goofy male protagonist falling in love with a girl who happens to reciprocate his feelings. In addition, both series feature a best friend of the protagonist who is a likeable guy and is usually very calm and collected. 

Both of these animes are feel good stories of highschool "social outcasts" attempting to make friends while each overcoming their own unique difficulties. Isshuukan friends focuses more on plot and character development while Boku wa tomodachi ga sukunai has more comical/fanservice aspects mixed into it. Both are very good animes and i would highly recommend both of them. 

Isshuukan Friends is more light hearted but both of them are focused on friendship. If you're a fan of Slice of Life anime you'll find this show wonderful. 

This anime gives many feels like NHK. Both MC are kinda beta and fail socially but its fun to watch. 

Similar hand-drawn art style; includes antisocial "loner" girls and guys who try to get close to them. 

- Both have a story about friendship. - Both have drama and are sad. - Both have characters with an unusual condition that gives them a lot of trouble - amnesia vs nacrolepsy. (A bit spoilerish) - Both have characters that keep forgetting something. 

Both animes potray a female protagonist that goes through school lonely and friendless. Through events, they both gain more friends and experience hardships and happy moments together.