Unlocking Charm

"There are many ways to pass through locked doors in the magical world (see the Fire-Making Spell, Gouging Spell, and the Reductor Curse) where you wish to enter or depart discreetly, however, the Unlocking Charm is your best friend."

- The introduction in the Book of Spells.

The Unlocking Charm, also known as the Thief's Friend (Alohomora) is a charm that unlocks and opens doors and windows that are not protected by magic. It is also able to open doors locked by the Locking Spell (Colloportus).

History
Although it is unknown who invented it (the spell was created in Africa) it was brought to Britain and hence to the world in the 17th century by Eldon Elsrickle. He used it to terrorise London, stealing from homes of Muggles and wizards alike, until Blagdon Blay invented the Anti-Alohomora Charm.

Prior to Alohomora, the most popular unlocking spell was Portaberto (used to splinter a lock from a door; though known to occasionally leave a smoking hole where the key should have gone) and, before that, Open Sesame (which ripped doors from their hinges and tore them into firewood). All of these were more rudimentary and by far less subtle than Alohomora.

Descriptions of this spell are written in numerous books, including the first volume of the Standard Book of Spells series, where it is described in chapter seven and a spellbook that can be found in the Hogwarts Library. This spell is also taught in Charms class to first years at Hogwarts school of Witchcraft and Wizardry and is one of the first spells students learn.

Counter-charm
There is a spell called the Anti-Alohomora Charm which is used to counteract this spell. Magical locks also existed and were placed on several doors, but could be unlocked with this charm.

Known practitioners

 * Eldon Elsrickle
 * Hermione Granger
 * Ron Weasley
 * Harry Potter
 * Lord Voldemort
 * Miriam Strout
 * Nymphadora Tonks
 * Unknown Death Eater (possibly Lucius Malfoy)

Etymology
J. K. Rowling stated that the word was from the West African Sidiki dialect used in geomancy and has the literal meaning "Friendly to thieves".

Behind the scenes

 * Alohomora Duo is a stronger version of this spell.
 * Although Dolores Umbridge's office at Hogwarts was (assumed) impervious to this spell in the novel, Harry Potter uses this spell to open it before attempting to use the Floo Network in the film adaptation of Harry Potter and the Order of the Phoenix.
 * As it was described in a textbook, this may be learned in Hogwarts Charms classes in the first year.
 * This may be the spell that Remus Lupin used to open a wardrobe containing a Boggart and the spell that Harry Potter used wandlessly to open his cupboard to retrieve his school supplies.
 * In the film adaptation of Harry Potter and the Prisoner of Azkaban, instead of using the Unlocking Charm to help Sirius Black escape, Hermione used Bombarda to blast open his cell door.
 * In the Chamber of Secrets video game for GameCube, Xbox, and PS2 it's specified that the Unlocking Charm is for use on mechanical locks. In most other sources, it's used on magical locks and the Locking Spell as well.
 * Also in the manuals for the video games, it lampshades the fact that not everything can be unlocked with the charm (such as certain doors and inaccessible areas), and thus tells the player to not get frustrated over this fact.
 * It is only in Chamber of Secrets, that only chests can be opened with the charm, while in the previous game, almost anything can be unlocked as long as it had to symbol for the charm's use. This was mainly that in the second game, the charm was to be optionally brought at Fred and George Weasley's Shop in the video games, and thus it would have little impact on locations that involve the story of the game outside of sidequests and hidden locations.
 * In LEGO Harry Potter: Years 1-4 and Years 5-7, the Reductor Curse is used to blast open most locks, instead of the Unlocking Charm.
 * According to Book of Spells, the spell Portaberto was the most popular unlocking spell before this, and prior to that Open Sesame was.

Appearances

 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Philosopher's Stone (film)
 * Harry Potter and the Philosopher's Stone (video game)
 * Harry Potter and the Chamber of Secrets
 * Harry Potter and the Chamber of Secrets (film)
 * Harry Potter and the Chamber of Secrets (video game)
 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Prisoner of Azkaban (video game)
 * Harry Potter and the Goblet of Fire (video game)
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Order of the Phoenix (film)
 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Deathly Hallows
 * Harry Potter and the Deathly Hallows: Part 2 (video game)
 * LEGO Harry Potter: Years 1-4
 * Harry Potter: Spells
 * Harry Potter Trading Card Game
 * Pottermore
 * Wonderbook: Book of Spells

Notes and references
Alohomora Alohomora Sortilège de Déverrouillage Алохомора Alohomora Alohomora