“They could hear footsteps, Filch running as fast as he could toward Peeves’s shouts.

“Oh, move over,” Hermione snarled. She grabbed Harry’s wand, tapped the lock, and whispered, “Alohomora!”

The lock clicked and the door swung open — they piled through it, shut it quickly, and pressed their ears against it, listening.”

- Harry Potter and the Philosophers stone

Why didn't Dumbledore bewitch the door to prevent Alohomora from opening it?

“And how are you going to get in there in the first place?' Harry was ready for this question.

'Sirius's knife,' he said.

'Excuse me?'

'Christmas before last Sirius gave me a knife that'll open any lock,' said Harry. 'So even if she's bewitched the door so Alohomora won't work, which I bet she has -”

- Harry Potter and the Order of Phoenix

  • 4
    My instinct is that he didn;t think to enchant it. The first door was just there to prevent accidental intrusion (by students who'd already been warned not to go there) rather than a concerted magical effort to stop Voldemort.
    – Valorum
    Commented Sep 18, 2015 at 23:32
  • 1
    I dont feel like making an answer atm but i think in the hospital wing after the confrontation someone said something about Dumbledore wanting Harry to confront Quirrel. Ron then called Dumbledore "Barmy" in an awed tone of voice.
    – Tdmut
    Commented Sep 19, 2015 at 2:18
  • 12
    Something that occurred to me is that it's possible Hagrid would need to get in to feed Fluffy and generally look after him. You could make Hagrid's life more difficult by requiring a teacher always to go with him and unlock the door, but it's not exactly gonna buy you any more security than what's through the trapdoor. It would have kept the students safer, though, but then, given Hogwarts's attitude to Elf and Safety (d'you see what I did there? :P) they probably thought: 'meh, doesn't seem like he generally attacks straight away. It's probably fine'
    – Au101
    Commented Sep 19, 2015 at 14:24
  • 1
    This is an excellent question;I have never thought about this before. I think Dumbledore would have bewitched the door at least to prevent the Weasley twins from getting in. It doesn't add up.
    – rah4927
    Commented Sep 19, 2015 at 19:49
  • 2
    How advanced is Alohomora? This is Hermione we're talking about...
    – DavidS
    Commented Oct 16, 2015 at 10:59

3 Answers 3


I'd say he didn't expect anyone to be stupid enough… but then I remembered Fred and George!

Actually, I think the only people Dumbledore trusted to handle Fluffy would be Hagrid and Professor Kettleburn (the Care of Magical Creatures teacher at the time), and after losing as many limbs as he has, Kettleburn would be none too eager to go near that animal. Given Hagrid's lack of advanced magical education, he wouldn't have been able to unlock some of the more complex locking spells without the help of another professor. Asking for a professor's help whenever Fluffy needed maintenance would have raised too many questions.

Finally, it's Hogwarts. The place is magic. It's got doors that will only open if you ask

  • 1
    Are Fred and George stupid? Or are they just reckless - and equally brave? I would say the latter two. But not stupid.
    – Pryftan
    Commented Aug 17, 2018 at 20:44

There could be many reasons to that. The one I think is that JKR wasn't sure if bewitching the door by Dumbledore himself will help the story line much. Moreover, if you think about it, eventually 3 first years kids managed to break all the enchantments and barriers created by wizards much wiser and experts in their fields :)

Secondly, I believe as the story progressed in the following books, JKR created new ideas of the wizard world that were meant to clarify the mysteries of the earlier books..like Sirius Knife to open the Alohomora Charmed doors - as mentioned above or the wagons from Hogsmeade station that were running on their own for 4 years suddenly started running by Thestrals in books 5. It is highly unlikely that in all the students of Hogwarts, nobody had seen a death of someone and nobody mentioned this to friends and nobody realized it that Thestrals were running the wagons!

As far as we know and Dumbledore himself said it too..things like these spread like wild fire in Hogwarts. So it is highly unlikely that students were, and so was Harry, unaware of the Thestrals situation.

I believe it was the story line and considering it was the first book of the series, things like these do happen.

  • 1
    Hi there, welcome to the site! This is very much an out-of universe explanation (and quite a good one). But I think, in this case (and in most cases on this site, actually), the OP was very much hoping for an in-universe explanation.
    – Au101
    Commented Oct 16, 2015 at 15:47

There's also the fact that Dumbledore wanted Harry to confront Voldemort. He wanted him to get the Stone by using the Mirror of Erised. So not using complicated enchantments and not locking the charm were all part of the plan. His plan to prevent Voldemort to return to true power...

  • 1
    I think you're attributing good fortune to intentional action. There's no good reason to assume that Dumbledore wanted Harry and Voldemort to come face to face.
    – Valorum
    Commented Nov 12, 2018 at 22:30

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