Song of Time

The Song of Time is a recurring song in The Legend of Zelda series. This song houses many mysterious powers that yield to different results depending how and where it's used. The Song of Time only appears as a playable song in Ocarina of Time and Majora's Mask, where only a part of the melody's abilities are fully explored. It is implied that this sacred melody is only known by members of the Royal Family of Hyrule and is taught to a selected few.

Ocarina of Time
In Ocarina of Time, the Song of Time is one of the three required items necessary to access the Sacred Realm from the land of Hyrule. Once the three Spiritual Stones are gathered, the Song of Time must be played in the altar of the Temple of Time by using the Ocarina of Time, which opens the Door of Time and leads to the resting place of the Master Sword. Link learns this mysterious song after he retrieves the Ocarina of Time that was thrown into the moat by Princess Zelda as she was escaping Hyrule Castle. Upon getting the ocarina, Link has a vision of the princess explaining her reasons for leaving, and teaches him the Song of Time through this telepathic message. With the Ocarina of Time and the three Spiritual Stones in hand, Link plays the mysterious melody to open the Door of Time, withdrawing the Master Sword to become the proclaimed Hero of Time.

The Song of Time can also be used to remove and bring back blocks that have the Door of Time's design on it.

Majora's Mask
Prior to the events of Majora's Mask, Princess Zelda hands over the Ocarina of Time as a memento of the times that she and Link spent together in the land of Hyrule. According to Zelda, the Song of Time holds a special meaning to her, and as such, she teaches it to the young hero before handing over the Ocarina of Time. Princess Zelda reminds Link to play the sacred song if anything were to happen to him, mentioning that the Goddess of Time will come to his aid.

The Song of Time is crucial in order to complete the game. By playing the Song of Time, Link can warp back to the dawn of the First Day at any given time or place. Any items or unused Rupees that are in possession when playing the song will be lost. However masks, weapons (except Razor Sword), songs learned, and other non-event items are kept. This melody must be played numerous times to free the Four Giants and save Termina from its impending doom.

Variations of the Song of Time
In Majora's Mask, a couple of tricks involving this song can alter the regular flow of time. Scarecrows will hint at these variations if Link chooses to speak with them. While they make progressing through the game easier, they are far from necessary to complete it.

When Link plays each note twice in the Song of Time, time will warp to the next instance of 6:00 am or 6:00 pm. This is known as the "Song of Double Time."

When Link plays the Song of Time backwards, all events directly related to the flow of time will move at half-speed. This affects the flow of time, and scripted movements such as Anju's movements, but not events that aren't directly involved with the flow of time such as an enemy's attack pattern or the rate at which Link can move. This variation of the tune is called the "Inverted Song of Time".

Twilight Princess
In Twilight Princess, it serves as background music for the entrance to the Temple of Time, and a remixed version is used in the battle against Ganon's Puppet Zelda.