Song of Time
How to Learn it
Ocarina of Time
After Link has acquired all three Spiritual Stones and attempts to enter Hyrule Castle Town, Princess Zelda flees with Impa on a horse, and throws the Ocarina of Time in the moat. Ganondorf will follow closely behind. When Link dives into the water to retrieve it, memories of Zelda will be created from the instrument, and she'll teach the song to him. The song can then be played in front of the altar in the Temple of Time, which will result in the Spiritual Stones placing at the hollows on the altar and the Door of Time opening.
After going through a sequence of events to open the Clock Tower as a Deku Scrub, Link will shoot the Skull Kid with a bubble. This causes the imp to drop the Ocarina of Time. When Link retrieves it, memories of Zelda come to him, and she teaches him the song. The song can be played to return to the Dawn of the First Day.
Ocarina of Time
It is also used, most notably in the Master Quest version, to move Time Blocks to complete puzzles in some dungeons.
The song will reset all the events of the three days and send Link to Dawn of the First Day. It will also wipe any progress he made in getting collectible items, such as Deku Nuts and Rupees. This prevents the moon from crashing into Termina.
There are two hidden songs, the Song of Double Time and the Inverted Song of Time. They are activated by learning the Song of Time. The Song of Double Time slows time down to move half as quickly. The Inverted Song of Time speeds time up to skip ahead in one 12 hour sequence.
How to Play it
In Ocarina of Time and Majora's Mask, it is played using the C buttons, like all the songs. It is played as follows: → A ↓ → A ↓.
In Ocarina of Time 3D, it is played as follows: Y L R Y L R.