Hi,

This is something that I've been wondering about for quite a while now, but does anyone know how the Trace, which keeps track of underage magic actually works? Like, when does it get cast on the wizards? And how is it checked?

 

We don't know much.

We do know that it works by detecting magic around the underage wizard, and even if not cast by him, it can be attributed to him. See the Dobby fiasco.

We have no idea how it's actually cast. But we do know that it automatically breaks when you hit 17, and it doesn't work on adults.

While at Hogwarts or on the train, the spells aren't tracked or recorder or however it works at the Ministry. Harry cast spells against Voldemort at the end of year four, which was out of school bounds, but still during the school year, so I guess that the notifications are just disabled while the school year is in place.

There are some inconsistencies. Multiple adult wizards have cast spells at Privet Drive during summer, but Harry hasn't gotten into trouble from that. Mr. Weasley and Tonks, at least. Mr. Weasley did inform the Ministry that they'd be coming there, he arranged the Floo after all, but I doubt that the Order told the Ministry that they'd be collecting Harry in the fifth book.

Ultimately, the Trace isn't something that has been really explained to us or reallly even elaborated on.

My personal guess is that it's something like the Taboo, a nation-wide spell that tracks any magic cast around underage wizards. We know that something like that can be done.

 

Yeah, as-described it doesn't make too much sense, but it's not hard to reason out a way for it to work. In TOHF I had it so the Ministry had actually cast an anti-apparition jinx on the area, but you don't need to go that far. We see later in DH that the Ministry had the power to completely collapse the protections on the Burrow, which means if they had taken Harry there illegally before his Trace was gone, the Ministry could have (and under Thicknesse, almost certainly would have) raided the Burrow and arrested much of the Order, as well as gaining direct control of Harry.

 

Trace is one of those things that's hard to figure out from canon. I personally just kind of gloss over it, like canon did. I mention it when I think it's relevant and don't try to work out what it does exactly, though I am partial to the idea of a nationwide magic radar.

In short, the Ministry has a list of residences of underage wizards and when magic happens in those places when they know the person should be there and as far as they know no adult wizard is there, they treat it as underage magic and send the letter. Very much an imperfect, easily fooled system (Dobby).

As for how they detect a specific person's underage magic outside their place of residence... I honestly just handwave it. So sue me.

The biggest problem with the Trace is that a good portion of the fandom still thinks it's an enchantment on the wand.

 

I don't hold with the wand theory, however off the top of my head it might come from Tom Riddle disabling Morfin Gaunt and then take his wand, kill the Riddles, and then skedaddle?

In other words underage Tom performed magic. In the Gaunts shack it wouldn't have triggered given the proximity of an adult wizard, and their residence. However once at the Riddles would the trace not reveal and underage wizard, Tom, was the only one about where magic occurred. That is if the trace was fixed to the person, and not the wand? I'd have to check, but Tom might have used Morfins wand not only for Priori Incantato but also for underage reasons.

A theory, probably similar to the radar, and to counter that very thought is that the Trace is less specific and refined. Perhaps the ancient and not totally understood magic of Hogwarts book "down since birth" is then passed on to the Trace department of the Ministry. Since it records a name perhaps that name is enough to work a specific magic to then monitor for magic about them. Or the idea mentioned of the location where they will reside. They are then fixed to that. So if magic happens in Little Whinging there is only one culprit in the area, but it is up to their discretion in other circumstances. In the Riddle instance Tom's trace wouldn't alert anything, neither would Harry in the graveyard because they are both far outside the perimeters marked for their monitoring. In the case of Tonks perhaps if someone performs an invisibility charm or an oft-used auror spell in Little Whinging then there might be a quick inquiry as to if anyone is about. Then there is the Patronus, but then the Ministry had that rigged anyway. As I keep thinking about it it keeps becoming more tangled, but hopefully that wasn't blatantly anti-canon.

The Ministry also knows specific spells, don't they? As with the hover charm? That might put some severe dampeners Dark, and otherwise embarrassing spells. Now I know why they don't have more kids, little buggers have to be shipped out or the parents leave themselves to do some magic they don't want the Ministry to see.

 

I always saw it as working in a radar sort of way like other people, but I think it's probably more something about an intrinsecly enchanted object. Something that acts as a sort of measure, that sees the direct workings of what happens around a young wizard. But, it's probably a lot more about who's around... Like, it has a mesurement about muggles and the like. And it probebly has some sort of mesure to tell if it's deliberit or not, because of accsidental magic...

 

It really is something that I have been breaking my head over, because every option I can think of only further complicates things. I guess that it would only be activated once a student enrolls at Hogwarts, Hermione for instance didn't get into trouble for already practicing, and it would lead to serious issues with younger siblings of muggleborns using accidental magic during the summer breaks of older siblings.

Reading this has convinced me that it must also be bound to locations, or at least, be focusing on locations, otherwise it will be a huge mess with all the reports coming in from all over the country, especially from magical households and locations. They would just overwhelm all other reports. I also really like the idea of a magical map, which gives a signal once someone actually uses magic on one of the monitored locations.

But the issue of it breaking on the seventeenth birthday remains, that means that it has to be cast on the person somehow. That points towards it being active on an individual level, so not on a location level. Which would also be a huge mess when muggle parents move around with their children. So, all spells used around the children are reported, which still causes a significant mess with adults around them. For magical-born children, they would just have to ignore everything, or perhaps they aren't even Traced, to prevent all the privacy issues for the parents. And it could of course be turned off during the school year, which would explain all the events where magic is used outside school during the year.

But yes, it is something that I really struggle with, because it is really hard to work it into a story about someone who is underage without making a chaos out of it.

 

Would have been nice to mention that there were those anti-apparition jinxes? Or why they could portkey from seven different locations but not from number 4? Or why as soon as they were in Tonks' house Voldermort just left?

 

When a wizard spell is cast, any wizard spell at all, the Trace will search in the immediate area with the radar centred around the spell, not the wand that cast it, not the wizard who used the wand to cast it, but around the spell. If it finds an underage wizard then it searches for an overage wizard. If no overage wizard is found then the Ministry is notified, but if an overage wizard is in the visinity then the Trace assumes it was them who cast it.

I specified that this is wizard spells because the Trace does not activate when an elf uses elf magic, if it did then Harry would have been getting letters when Dobby Apparated in and out of Privet Drive. However, the reason it detected his Levitation Charm was because Dobby cast that spell with wizard magic which he learned through watching Draco practice. Dobby casted the wizard spell because he was trying to get Harry expelled so he wouldn't return to Hogwarts.

The Trace is also used to track a pre-Hogwarts wizard's accidental magic. If an overage wizard is near then chances are they can deal with it otherwise the Ministry officials take a look at what happened and deal with it accordingly, probably Obliviting everyone of their presence too, hence why Harry never recalled any Obliviators.

The Trace, like the Taboo, is a Ministry-run wide-area spell.

The majority of this is, of course. Headcanon and speculation but I find that it works, unless there is a hole I'm not seeing.

 

The hole is that we're specifically told the Trace is on people and breaks at 17.

 

It's true, but the idea that the Ministry isn't even notified when there is an adult wizard in the vicinity may have merit, I think.

Going with the magical radar analogy, adults could act like jammers and prevent the Trace from working at all. It would explain how the Ministry didn't know there was an underage wizard present when the Riddles were killed.

I'm not sure it is compatible with the way Dumbledore explain it, but I think it explains all the usual issues (Mr Weasley and the Order, Harry in the graveyard and with Dumbledore, Voldemort with the Riddles and Morfin). Does it work, or am I missing something important?

 

Yeah, canon is pretty disappointing in how it describes the Trace, and there are some inconsistency. The one thing that is definite, though, is that the Trace can be fool, and isn't the most accurate thing. I don't think it's cast on the Wand, since Dobby's Hover charm was able to trigger the trace.

I agree with some of the post here that describe it as a radar. I imagine that there's some large spell over Britain that detects all form of magic. Anytime there's magic, it somehow see if there's an overage Wizard nearby, if it's an underage Wizard, they automatically get caught. I remember somewhere that Privet Drive is mainly Muggles, so it was easy for Harry to be blame for the spell.

It's probably how new wizards/witches are found. Accidental magic is perform, no overage wizard nearby, large muggle population, and no record of an underage wizard. All of this automatically warrant a visit from the Ministry to do damage control.

 

On the other hand there are no warnings sent for Harry in GoF, OotP or HBP when adult wizards use magic in Privet Drive.

Canon really is not consistent with anything relating to magic.

 

What about Hermione using spells with her wand before Hogwarts?