Okay peeps this is a pretty big debate in the anime fandom. What classifies as a shojo series or a magical girl series?

Let the debate begin! 

The way I see it, Magical Girl must have the following traits

-A female lead who uses magic to HELP solve problems. 
Take Minky Momo for example. She uses her powers to transform into an older form so the people she wants to help won't just say "A little kid can't help me." But from there she had to win a horse race without turning the horse magical and letting it fly over the arena. XD In the case of a MG Warrior I can understand if magic's more focused on, but they do try their best to help people with their own abilities, usually talking to people with problems.

-Love and Friendship!
You can't have a magical girl series without characters who despite the occasional arguments, do care about each other and work together. Sometimes their powers will increase with their love and friendship. There's no set limit, it's all about the strength of the user's heart. Usually the final battle puts all of their love and determination to the test. 

-Costumes~
These are a given for the Warrior and Idol types. An Idol singer needs a fancy dress and a warrior needs a costume to change into, as per their Sentai inspiration. They sometimes have secret identities, but aside from Precure, not too much effort is made in disguising. Cute Witch types are more prone to wearing normal clothes, especially if they come from another world.

-Maturation of character.
For me, a Magical Girl anime is about how magic helps the protagonist grow as a person, with or without magic. Usagi of Sailor Moon for example grows from being a total flake, to a strong and determined young woman. Same goes for Tsubomi of Heartcatch Precure, who starts out as a timid and insecure young girl, but as the show goes on realizes her determination to change herself. If the main character is completely fearless and strong at the beginning, or stays a pathetic crybaby the entire series, it falls flat.


As for what makes a series a shoujo series, that's a matter of target demographic. If the series is specifically made for the shoujo demographic (young/teen girls), like published in a manga magazine such as Nakayoshi, it's definitely shoujo.

Lilith has a spell for that! ^_^; Well, actually Lilith can do that with her old spell...

Makahari Mahora Lila Lili Makara!

Shoujo means a series made specifically to girls. To count, unlike what you think, you don't need to have love as the main part. Shoujo series are:

A) Beautiful people: Shounen usually prefers menacing looking or muscular people as the leads. If females, these female will mostly be sexy. Shoujo focuses more on handsome and cute, good looking without going too extreme.

B) "Sensible" and feeling-centric: No, it doasn't mean excessive feelings. It's more like plot focuses more on the characters and their feelings rather than action, which get's left in a second life or not appearing at all.

Mahou Shoujo are usually considered a sub-genre of Shoujo, but several of the series are definitively NOT Shoujo. As it happens with Mecha respect of Shounen, Mahou Shoujo can contain series that are definitively not Shoujo. For example, there are several magical girls that are considered Hentai or maybe seinen. Thing is that people confuses about the classifications of stories:

Seinen, shounen, hentai, shojo, kodomo and yosei are DEMOGRAPHIC categories, which means you can't have a shoujo-shounen, for example.

Mecha, Harem, Magical Girl and the so are CONTENT categories and are more related to what they have in. These can crossover without problem (there are at least 2 Mecha Magical Girls series on the somewhat new series). It's like when we have monster movies, alien movies and the so. And according to Monsters vs. Aliens, it works.

To qualify a series, one must pick one of the demographic categories and the content categories that might fit.

Lilith out!

Makahari Mahora Lila Lili Makara!

POOF!

I have noticed throughout tumblr that people are debating that Tokyo Mew Mew is not a magical girl series because the girls' powers come from science not magic. And their point? The mews fight to protect the ones they love and the planet. The show teaches about friendship and slightly touches the importance of protecting the environment. Love is also big theme in the series because Ichigo comes across different types of love. So yeah TMM covers all the points RLink brought up.

Lilith I like your points. Usually people dont classify a series that way. 

Personally to me a magical girl show is a show about girls helping people with special powers. Whenever that be transforming into a super hero or using their powers to help friends and family. I think some fans forget that a magical girl doesnt have to fight evil. A good example of this is the Ojamajo Doremi series. Doremi and her fellow witch friends use their magic to help their classmates and family members. It also teaches kids live meaningful lessons.

Mew Ami wrote:

I have noticed throughout tumblr that people are debating that Tokyo Mew Mew is not a magical girl series because the girls' powers come from science not magic.

The same goes for Lyrical Nanoha and Madoka Magica. The first one has the "magic" made from science and the other one has the girls receive their powers from a space alien. Those things alone don't exclude them from being considered Magical Girl shows.

Exactly!

Indeed, those things are not detriment of what a Magical Girl is. If you wanna take a good example, Lilith sets two to discuss: ESPer Mami and Miracle Shoujo Limit-chan. Those two are widely accounted as Magical Girls, yet Limit's powers come from technology (she's a cyborg a la Robocop but cuter and less metallic), which had been hinted since episode one and Mami is a psychic (ESPer comes from ESP or Extra Sensorial Powers; in fact, you can do a dub of it and call it "Psychic Mami" without being out of place) who would be very fitting in the X-Men.

Yet they are Magical Girls of the Cute Witch style (i.e. they focus on fixing normal problems and live their normal lives with their powers), just like Sally, Megu, Lalabel... all of them Lilith's Sempai-tachi. Ask anyone from the 80s or 90s and they'll mostly agree Limit and Mami are Magical Girls. Yet they lack of several elements that were made into Magical Girl staples several years later. If you grab the Magical Girls of the past and bring them to the discussion, it makes all the "controversial" series all the more fitting in the genre. If Mami's a Magical Girl, then Nanoha, Madoka and Ichigo are no less magical girls than the rest.

I'll just leave this here.

Thanks, Tomoyo-chan!

To me (and yes I know others have mentioned this)

Shoujo is just a demographic for girls. Thus publishers/producers try to appeal to women by using themes they can relate to. But I don't think there's any kind of set in stone rules, these things change with time. And like we should all know, every girl is different and not everything can appeal to every girl. If anything the title of "Shoujo" and "Shonen" is completely pointless for audiences and only put there for the advertisers to have some kind of focus.

 For example CLAMP's X series, which ran in a shoujo magazine featured - explosions, blood n guts, male "the chosen one" protagonist, spiritual powers and battles, romantic undertones and lots and lots of pretty boys. There was a female lead in it, but she's killed on-screen by the midway point and that's actually when the series reached its popularity.
On the other end of the spectrum, CLAMP's Suki, Dakara, Suki (also ran in a shoujo magazine) was much more of what we've come to expect (Romance, quirky female lead, teddy bears, jealous best friends and drama, overall heartwarming tone)
The two could not be further from each other but still fall under the same demographic umbrella.

 
Magical Girl, which started as a Shoujo trope in order to re-brand Bewitched for little girls has a much more interesting evolution because by 1985 there was suddenly a home video market and the powers-that-be realized that anime could be marketed exclusively to adults who still felt connected to the anime they watched as kids. The magical girl trope/genre included. 
But really, without the influence of the "Shonen" demographic the Magical Girl genre would be so much different. Since the idea of girls using magic to fight started in Cutey Honey - a show that was going to be aimed at girls, but was quickly arranged to market to boys when there was demographic scheduling problem. (Honey still became popular with girls anyway btw)
All the tropes we've come to know and love (transformations, inner drama, etc.) evolved from a previous show doing it and it being popular. Simple as that. 


That aside though I think Magical Girls can be picked out if they have: a Young Female Protagonist who uses An unexplainable or extraordinary power to make a positive influence for herself or her surroundings.  Of course if your parodying this ideal, different rules apply. Also since the whole thing is Bewitched's fault any show that's about a witch girl automatically gets put in the genre.

For the debate on "But wait! that's science!" for TMM and even Cutey Honey. I think if the "science"
 is limited to a select few and that it's so advanced that viewers sense of realism is suspended (Heck, I'm sure most of the writers can't even really explain it) then it freaking counts as magic.

BunnyBelle wrote:

For the debate on "But wait! that's science!" for TMM and even Cutey Honey. I think if the "science"
 is limited to a select few and that it's so advanced that viewers sense of realism is suspended (Heck, I'm sure most of the writers can't even really explain it) then it freaking counts as magic.

Lilith already explained two series that are totally Magical Girls, yet one is about a cyborg (Limit-chan) and the other one has a straight out superheroine without disguise (ESPer Mami). If those are Magical Girls, TMM and Cutey Honey are totally in the genre.

As far as I have noticed, other than magic and how it is used, the target demographic is the biggest point of difference. Mahou shoujo series that are primarily geared towards girls tend to favor girls aged 6-14, most shoujo series are meant for older girls in the 14-18 age range as readership dies down during the high school years.  

Of course I am using shoujo in a narrower sense than it's true broad spectrum, specifically just manga geared towards a young female audience.