- "A long time ago... There was a man in this very village who had an eye they said could see the truth! Now usually, you have to train your mind's eye most strenuously to actually see the truth... But this fella, no, they say he had a different way of doing things... His house stood where the well is now..."
- — Shikashi
The Lens of Truth is a recurring item in the Legend of Zelda series. It is a magical lens crafted by the Sheikah that can see through any illusion, such as hidden doors, pits and other things. It may also be used to ascertain the contents of a large Treasure Chest before opening it, thus allowing Link to avoid trapped chests. The Lens of Truth will slowly drain the user of magic power. It acts only in the middle of the screen, and will also prevent the use of other magical abilities when active. In some regards, it is similar in function to the Cross from Zelda II: The Adventure of Link.
Link is first told of the Lens of Truth by Shikashi in Kakariko Village. He tells Link about a man who had an "eye that could see the truth." His house once stood where the Well of Three Features lies in the present time. As a child, Link must brave the many dangers of the Bottom of the Well in order to obtain it.
While obviously harder, it is possible to complete the game without ever obtaining the Lens of Truth, by simply memorizing where the hidden paths, platforms, and other invisible objects are, or by using trial-and-error to solve such puzzles. This process becomes extremely problematic when Link must cross the Haunted Wasteland, as the maze-like way forward is shown by a Phantom Guide who may be seen only with the Lens of Truth. Another difficulty appears in certain puzzles in the Shadow Temple, involving randomness in the placement of illusory or invisible objects.
Link can also use the Lens of Truth to easily win the Treasure Chest Shop mini-game. When activated, the Lens allows Link to look through a treasure chest and see its contents; using this method, Link can always be certain of which chest contains the Small Key needed to advance to the next room. This field of usage is hinted at by a Gossip Stone.
The Lens of Truth is found in the Lone Peak Shrine, across the chasm from Goron Village in Snowhead. Link must follow Kaepora Gaebora's feathers to safely find the hidden platforms leading to the Shrine. After retrieving the Lens of Truth, Link must now put it to use to locate the hidden platforms leading back to Goron Village, as the owl's feathers are now gone. Upon his return to Goron Village, he is able to see the ghost of Darmani with the Lens of Truth; Darmani's spirit guides Link to the Goron Graveyard, where Link heals Darmani's soul, sealing his spirit inside the Goron Mask.
A Clock Town Soldier named Shiro can be found on the Road to Ikana. He can only be seen with the Lens of Truth, and if Link brings him a Red or Blue Potion, he will give Link the Stone Mask as a reward for enabling him to "stand out". Subsequently, he may be seen without the use of the Lens of Truth. In Majora's Mask 3D, Shiro is found in the Pirates' Fortress instead of Road to Ikana, though his role is basically the same and the Lens of Truth is still required to see him.
As the game contains no trapped treasure chests, the capability of the Lens of Truth to reveal their contents is less important than in Ocarina of Time. While the uses for the Lens of Truth are not as pronounced as in Ocarina of Time, unlike in that game, using the Lens of Truth is absolutely mandatory to progress, as it must be active to speak with Darmani's ghost.
The Lens of Truth makes a brief appearance in Hyrule Warriors, in The Water Temple story scenario. Princess Ruto reveals that it was left in the temple by the legendary hero (presumably either the Hero of Time or the Hero responsible for splitting the King of Evil's Soul) and decides to go after in order to use its power to reveal the imposter Zelda's true form, but is trapped in the temple's central hall shortly after finding it, forcing the allied forces to rescue her. The Lens reveals a hidden path to the Hall of Mirrors, where the fake Zelda is based. After the fake Zelda is defeated, Sheik uses the Lens' power to reveal the imposter as Wizzro. Afterwards, Sheik hands the Lens to Impa and reveals her identity as the true Princess Zelda. It is last seen in Impa's possession. The Lens design is different from the original, resembling more of a mirror than a magnifying glass.
An 8-bit version appears in Adventure Mode as a cursor that appears over a square that has not been unlocked.