Key

The Key is a small but crucial object in the quest of Thorin and Company, a physical token of the lost heritage of the dwarves and the means by which the adventurers gain access to the Lonely Mountain. Forged with intricate wards and a long barrel, it is made of silver and was originally entrusted to Thrain, Thorin's father, who passed it to Gandalf for safekeeping. Its existence is the linchpin of the entire enterprise, transforming a vague hope of burglary into a concrete possibility, and its eventual use marks the climax of the long journey from Bag-End to the Mountain's hidden door.

Origin and Custody

The Key was given to Gandalf by Thrain, Thorin's father, when the wizard found him a prisoner in the dungeons of the Necromancer. Thrain was witless and wandering, having forgotten almost everything except the map and the key. Gandalf kept the key for a hundred years, waiting for the right time and the right heir to deliver it. At the Unexpected Party in Bilbo's hobbit-hole, Gandalf presented the key to Thorin, who fastened it upon a fine chain that hung about his neck and under his jacket, keeping it safe against the day it would be needed.

The Key and the Secret Door

The Key is specifically designed for the secret entrance on the western side of the Lonely Mountain, a passage too small for the dragon Smaug to use. The map of Thror, also given to Thorin, bears runes that describe the door as "five feet high the door and three may walk abreast," and the key is the only means of opening it. The dwarves' search for the door is long and wearying, and their spirits sink as they fail to find any trace of it on the smooth rock-face. It is only when Bilbo, sitting on the "doorstep" of the grassy bay, notices an old thrush knocking a snail against a grey stone that he remembers the moon-letters read by Elrond: "Stand by the grey stone when the thrush knocks, and the setting sun with the last light of Durin's Day will shine upon the key-hole."

The Opening

As the sun sets on the last day of autumn, a red ray of light escapes through a rent in the cloud and falls on the smooth rock-face. A flake of rock splits from the wall, revealing a hole. Thorin hurriedly draws the key from its chain and puts it to the hole. It fits and turns with a snap, and the rock-wall gives way, revealing a door five feet high and three broad that swings inward, leading into the darkness of the Mountain. The Key thus fulfills its purpose, granting the company entry to the dragon's lair and setting the stage for the final acts of the adventure.

Significance

The Key is more than a mere tool; it is a symbol of the dwarves' lost kingdom and the rightful claim of Thorin's line. Its journey from the withered hands of Thrain to the neck of his son represents the passing of hope and responsibility across generations. The fact that Gandalf, not Thorin, held it for so long underscores the wizard's role as a guide and catalyst, while the key's eventual use on Durin's Day ties the success of the quest to the ancient lore and calendar of the dwarves. Without the Key, the secret door would have remained an impenetrable wall, and the entire adventure—the riddles in the dark, the escape from the goblins, the journey through Mirkwood, and the arrival at Lake-town—would have led only to a dead end.