<p>As the comments say, this is a somewhat subjective question. I'll give my own reason, which I think is a big part of the reason this is common, but perhaps not the only reason.</p>

<p>Japanese society is more regimented than one might believe just from watching anime. By middle school age, and even to some degree in primary school, children are expected to interact with their peers in a relatively professional way. This is especially true of relationships between students of opposite sexes. Such requirements aren't held for family or close friends, but for everyone else one is expected to be polite and not share their true feelings or say things too directly.  This concept of dividing people into an in-group and an out-group (<a href="http://en.wikipedia.org/wiki/Uchi-soto" rel="noreferrer">内外, <em>uchi-soto</em></a>) is somewhat hard for non-Japanese people to understand, but is central to interactions between people in Japanese culture. In fact, you can find plenty of examples of this and of the related concepts of <a href="http://en.wikipedia.org/wiki/Honne_and_tatemae" rel="noreferrer"><em>honne</em> and <em>tatemae</em></a> in anime if you look, but if you aren't looking for them specifically it's easy to miss.</p>

<p>It's difficult for a person in the out-group to enter the in-group. While not impossible, generally this takes time and effort. The groups aren't a simple dichotomy either; they change depending on the situation. It's especially difficult for close friendships between members of the opposite sex to form. One way for this to happen is for the two to enter into a relationship, but this is obviously not ideal if you want to make a romantic comedy where the characters aren't already in relationships. Another way is for one person to act closer to the other than they really are, as a way of testing the boundaries, but that person is being somewhat rude in doing so and it can backfire.</p>

<p>The most realistic way for a character to have a close friend is for them to be long-time friends. Specifically, if their friendship goes back all the way to childhood, when they didn't have to follow these strict rules, a friendship could develop without much issue.  Having a childhood friend character is one way to get a character who is already part of the protagonist's in-group. From a writer's standpoint, this is an attractive proposition, since it gives someone that the protagonist can have relatively serious conversations with, but who can also be a potential romantic interest. In (reverse) harem shows, it's especially attractive to diversify the female (male) cast of romantic interests.</p>

<p>That said, I think we have been seeing something of a decline in recent years in this archetype, at least among harem shows. Probably writers have realized that it's overused and that a generic <em>osananajimi</em> character without any unique personality traits isn't a very interesting character. Opposite-sex childhood friends are also far less common in real life than in anime, making the prevalence of this somewhat unrealistic. 10 years ago, nearly every harem/romcom show had a character like this, but the proportion seems to have dropped to less than half of them today. Partly, this can be attributed to other archetypes increasing in popularity (notably, the little sister/<em>imouto</em> character, who can be even closer to the protagonist than a childhood friend). When they do show up in shows today, it's often as a dual archetype character, e.g. a <em>tsundere osananajimi</em>.</p>

CC BY-SA 3.0
2014-12-20T09:35:20.173Z
Thank you for such a detailed answer (and [two](http://anime.stackexchange.com/questions/16885/who-applies-censorship-on-an-ecchi-anime#16916) in a single minute, hmm). Also, agree with the declining use of the trope in favor of *imouto* character in recent years.
romcom_god
CC BY-SA 3.0
2014-12-20T09:10:28.323Z
2014-12-20T09:10:28.323Z
Logan M
<p>I've noticed that most anime, especially in genres like slice of life and romantic comedies,  there is at least one character that plays  the role of the childhood friend (osananajimi). This is often coupled with the unrequited love, girl next door, or other related <a href="http://tvtropes.org/pmwiki/pmwiki.php/Main/PatientChildhoodLoveInterest?from=Main.Osananajimi">tropes</a>.</p>

<p>Of course, childhood friends are in every culture out there, but I'm curious if Japan has a special reason for this particular occurrence in anime shows. Also, aside from gender inclination towards the shounen genre, why is it that most osananajimi are girls whereas in real life, our childhood friends are typically of the same sex? Is this occurence more prevalent in Japan than in other cultures?</p>

<p>And feel free to edit (especially the title) and/or comment if this question is off-topic.</p>

CC BY-SA 3.0
2014-12-03T15:37:22.980Z
Sorry, I too, wasn't sure if this question is off-topic or not. Someone can close it if they're sure it is. I'll wait for a couple hours and be back here. And except for the Japanese-relevance side of the question, I guess I did sorta answer my own question there unknowingly. Huh.
romcom_god
CC BY-SA 3.0
2014-12-03T15:38:28.047Z
Another problem: your title and your question body asks 2 different questions.
nhahtdh
CC BY-SA 3.0
2014-12-03T18:08:06.083Z
This is a tricky question to tackle, because of the potential for subjective answers is much greater, especially across different culture. It seems to me that the "osananajimi" concepts is more representative of what Westerners perceive as "true friendship," one where nothing needs to be explained and trust is unshakable. Japanese culture is steep with propriety traditions and whatnot (inner/outer relations), a lasting and developed friendship that draws upon innocence of childhood is unlikely to develop later on in life, as you get bogged down by obligations and expectations.
кяαzєя
<anime-production><tropes>
Why is the childhood friend trope commonly seen in anime?
# Why is the childhood friend trope commonly seen in anime?
Posted by: username_0 on 2014-12-03
I've noticed that most anime, especially in genres like slice of life and romantic comedies, there is at least one character that plays the role of the childhood friend (osananajimi). This is often coupled with the unrequited love, girl next door, or other related [tropes](http://tvtropes.org/pmwiki/pmwiki.php/Main/PatientChildhoodLoveInterest?from=Main.Osananajimi).

Of course, childhood friends are in every culture out there, but I'm curious if Japan has a special reason for this particular occurrence in anime shows. Also, aside from gender inclination towards the shounen genre, why is it that most osananajimi are girls whereas in real life, our childhood friends are typically of the same sex? Is this occurence more prevalent in Japan than in other cultures?

And feel free to edit (especially the title) and/or comment if this question is off-topic.
**Tags:** anime-production tropes
> **Comments:**
> **username_0**: Sorry, I too, wasn't sure if this question is off-topic or not. Someone can close it if they're sure it is. I'll wait for a couple hours and be back here. And except for the Japanese-relevance side of the question, I guess I did sorta answer my own question there unknowingly. Huh.  
> **username_1**: Another problem: your title and your question body asks 2 different questions.  
> **username_2**: This is a tricky question to tackle, because of the potential for subjective answers is much greater, especially across different culture. It seems to me that the "osananajimi" concepts is more representative of what Westerners perceive as "true friendship," one where nothing needs to be explained and trust is unshakable. Japanese culture is steep with propriety traditions and whatnot (inner/outer relations), a lasting and developed friendship that draws upon innocence of childhood is unlikely to develop later on in life, as you get bogged down by obligations and expectations.  
---
## 1 answers
### Answer by username_3 on 2014-12-20. Score: 5 | Accepted answer
As the comments say, this is a somewhat subjective question. I'll give my own reason, which I think is a big part of the reason this is common, but perhaps not the only reason.

Japanese society is more regimented than one might believe just from watching anime. By middle school age, and even to some degree in primary school, children are expected to interact with their peers in a relatively professional way. This is especially true of relationships between students of opposite sexes. Such requirements aren't held for family or close friends, but for everyone else one is expected to be polite and not share their true feelings or say things too directly. This concept of dividing people into an in-group and an out-group ([内外, *uchi-soto*](http://en.wikipedia.org/wiki/Uchi-soto)) is somewhat hard for non-Japanese people to understand, but is central to interactions between people in Japanese culture. In fact, you can find plenty of examples of this and of the related concepts of [*honne* and *tatemae*](http://en.wikipedia.org/wiki/Honne_and_tatemae) in anime if you look, but if you aren't looking for them specifically it's easy to miss.

It's difficult for a person in the out-group to enter the in-group. While not impossible, generally this takes time and effort. The groups aren't a simple dichotomy either; they change depending on the situation. It's especially difficult for close friendships between members of the opposite sex to form. One way for this to happen is for the two to enter into a relationship, but this is obviously not ideal if you want to make a romantic comedy where the characters aren't already in relationships. Another way is for one person to act closer to the other than they really are, as a way of testing the boundaries, but that person is being somewhat rude in doing so and it can backfire.

The most realistic way for a character to have a close friend is for them to be long-time friends. Specifically, if their friendship goes back all the way to childhood, when they didn't have to follow these strict rules, a friendship could develop without much issue. Having a childhood friend character is one way to get a character who is already part of the protagonist's in-group. From a writer's standpoint, this is an attractive proposition, since it gives someone that the protagonist can have relatively serious conversations with, but who can also be a potential romantic interest. In (reverse) harem shows, it's especially attractive to diversify the female (male) cast of romantic interests.

That said, I think we have been seeing something of a decline in recent years in this archetype, at least among harem shows. Probably writers have realized that it's overused and that a generic *osananajimi* character without any unique personality traits isn't a very interesting character. Opposite-sex childhood friends are also far less common in real life than in anime, making the prevalence of this somewhat unrealistic. 10 years ago, nearly every harem/romcom show had a character like this, but the proportion seems to have dropped to less than half of them today. Partly, this can be attributed to other archetypes increasing in popularity (notably, the little sister/*imouto* character, who can be even closer to the protagonist than a childhood friend). When they do show up in shows today, it's often as a dual archetype character, e.g. a *tsundere osananajimi*.
> **Comments:**
> **username_0** (2014-12-20): Thank you for such a detailed answer (and [two](http://anime.stackexchange.com/questions/16885/who-applies-censorship-on-an-ecchi-anime#16916) in a single minute, hmm). Also, agree with the declining use of the trope in favor of *imouto* character in recent years.  
---
