Oly Oly Oxen Free

Oly Oly Oxen Free is a six note, seven beat tone used as an all clear code by the Spartan-IIs. They learned it from Deja on Reach when they were younger and have been using it ever since.

Psychology
Oly Oly Oxen Free was a secret amongst the Spartans. They, and a select few outsiders knew it. Those outsiders were close to the Spartan's family; such as Dr. Catherine Halsey, Cortana, Sergeant Johnson and Chief Petty Officer Mendez. Thus, the signal was extremely important to each Spartan; they would rather die than give up the significance of the tone, which could potentially be used to betray or endanger their teammates. They learned this tune/code from their AI instructor, Deja, while they were training on Reach.

Uses
The term Oly Oly Oxen Free was used on numerous occasions throughout Halo: First Strike. Some of the times it was used are as follows:


 * After the Spartan Team had beaten Tango Company and John-117 had checked to make sure their evacuation point was all clear.
 * After the Battle of Reach, Anton-044 used it as an S.O.S. signal over the E-Band.
 * In order to allow the Spartans to enter CASTLE Base, Kelly-087 used it to let Dr. Halsey know it was them.
 * During Operation: FIRST STRIKE, Linda-058 used it to let John know where she was so he could find her and pick her up.
 * At the end of Operation: FIRST STRIKE, Sergeant Johnson used it to let Blue team know that the Gettysburg was holding station behind a nearby moon.
 * When the rest of Blue Team, minus John-117 arrives on Onyx, Kelly whispers "Olly Olly Oxen Free" (probably a misprint as it is spelt with only one L), over the COM.

Non-Canon Use
Marines use it on the level "The Ark" when firing on the first Covenant encampment, as well as in Crow's Nest, but only if the IWHBYD Skull is activated.

Trivia

 * Dana Awbrey alludes to this phrase by titling a blog post "Olly Olly Axon Free".
 * Oly Oly Oxen Free was originally used to tell players in a game of hide and seek that the game was over and they could come out of hiding.
 * Sometimes in Tom Clancy's Splinter Cell, if you shoot an enemy and then hide, they will say "Oly oly oxen free! Come out, come out wherever you are!".
 * This phrase was used in Kurt Vonnegut's book Mother Night.

Related Links

 * Spartan Language

Oly Oly Oxen Free