I’ve watched a lot of anime, and one thing that’s had me puzzled in many of the shows featuring high schoolers is how the kids are living by themselves. Aren’t they a bit young for that? Where are their parents? Are they dead, or are they just not around, or is it common for parents in Japan to let their children live alone? I don’t know enough about how things typically go there even to venture a guess.
The lack of parents is usually either a psychological trigger for certain personalities (I.E. the loner with neglecting rich parents, the young boy trying to grow up, etc) or just an excuse for making possible situations like women staying over is romance comedies without worrying anyone (Not like anything actually EVER happens) or for the typical monster hunter/secret agent/random fighter guy to go battle at any hour of the day and vanish for unexplainable amounts of time without having to give excuses.
As for reality: No, it’s not normal. No more than anywhere else at least. It’s just a cheap writing trick to save them the trouble of working around said problems. The slightly softened trick is the oblivious/impossibly-comprehending parents that treat all anomalies as “Oh well, it’s part of youth~”, like Yuuji’s mother in Shana, who sees his son’s sudden bursts of fatalistic thoughts, unexplicable interest in battle training and colorful acquaintances as if they were nothing.
The population density of Japan is like ten billion per square feet. “Living by yourself in a big house” is just a fantasy that the writers come up with and also a convenient plot device for non-parental-interference
The Animes where the parents do anything meaningful are few. I’m reminded of the 80’s series Video Warrior Laserion (Super Lasser in Spanish) where the hero was the typical preteen-kid-who-is-the-only-one-who-can-pilot-the-Main-Robot, and his mother did not know. (She was also fat, another unusual thing in this type of Anime.) However she DID notice her son’s odd behavior and in one Episode, looked around for him and almost got caught in one of the battles. Nice touch from the writers.
(One especially weird case in my opinion.)
In Inuyasha, Kagome’s mom is way too understanding. She knows Kagome is going off for weeks at a time with some strange guy and I think she even knows that Kagome is somehow going into a magic well. She may even know that Kagome is almost killed many times too! And she doesn’t do a thing about it.
I always thought it was metaphorical for the alienation adolescents feel. Or something like that.
See, I was willing to let it go for the ones where the characters are college-age, but for high schoolers? No way…
Originally Posted by Fullmetal
(One especially weird case in my opinion.)
In Inuyasha, Kagome’s mom is way too understanding. She knows Kagome is going off for weeks at a time with some strange guy and I think she even knows that Kagome is somehow going into a magic well. She may even know that Kagome is almost killed many times too! And she doesn’t do a thing about it.
She and the whole family knows that Kagome visits the other world with the guy with cute dog ears. If you had watched the third or fourth episode you might’ve known that. Kagome’s friends however have no clue that she’s tripping down a well (until she starts telling then of her new violent boyfriend which they occasionally meet but that’s as far as it gets so far…).
That example serves better as an example of the missing parent cliche where one parent is raising the main character (sometimes something happens to them) while the other parent is usually tied to the story as a major character in some way (and almost always responsible for the main characters importance though there are exceptions). Other relatives are optional though.
Other unusual examples:
In Pokemon, adults are perfectly OK with 10-year-olds going off on their own around the world “as long as they have their Pokemon with them!” Riiight. Of course, that’s some alternate Earth, ala Naruto. I guess it’s a tradition there…
In MARCHEN AWAKENS ROMANCE, the hero’s mother writes fantasy novels for a living, and his son eats them up, and she gets mad at him for daydreaming about being a hero. She’s also probably angry at the fact his father ‘left’ them years ago. Except of course, there really is a magical world, and the kid’s father went there to be a Hero, and now it is his son’s turn to go there and save the world. 
And in YuYu Hakusho, the main hero’s mother was a lazy drunk, and Yusuke thought she didn’t give a damn about him, and it was until he died that he realized how much she (and the rest of people he knew) loved him. Luckily he got the chance to come back to life, though his mother was never exactly a role model.