Purging

Purging, more commonly known as Purge パージ (paaji), is an special technique that Reyvateils can use to increase their powers, which is done through the shedding of parts of their clothing. The farther they Purge, the stronger their Song Magic will become.

Technical Explanation
In technical terms, this is done through an special linkage with the Wills of Ar Ciel made through special high-level waves called U-Waves. These waves allow the Reyvateils to synchronize with the Planet, and in turn, its Wills will lend them more power, which manifests by raising their output of Dynamic H-Waves. This in turn accelerates the output of Dynamic D-Waves the Tower will send to them, dramatically increasing their power, up to the point in which they will be able to superimpose a section of their Cosmospheres over the real world, executing a devastating kind of Song Magic called Flipsphere.

Disadvantages
Despite these benefits, Purging has two major disadvantages: the first one being that it's an extremely embarrassing experience for the Reyvateils and as such, they won't agree to execute a Purge if their partner hasn't cleared enough levels of her Cosmosphere first. If a Purge is executed without the agreement of the Reyvateil, the Song Magic will explode out of control, and its power level will decrease.

The second disadvantage is that this power is only available for Reyvateils that have been linked with the Wills of Ar Ciel, which only happens if they were created as mere containers for a Will to manifest in the physical world, or if the Reyvateil has its Cosmosphere linked to the Antibodies that Ar Ciel created for its self-protection.

In other words, only the Reyvateils Saki, Finnel, and Tyria are capable of using this technique, and after the events depicted in Ar tonelico Qoga: Knell of Ar Ciel, given that the Wills have already fulfilled their purpose and will abandon the physical world to return to the Planetary Core, they lose the ability of performing it.

Conditions for Being Executed
During a battle, the music playing in the background, regardless of if it's a Song created by Hyumas programmed by the player, or an Hymmnos Extract played for story reasons, will be reflected in the Harmograph that can be seen in the lower part of the screen. Every now and then, high frequency bars, represented in red, will pass through it. If the player executes an attack when a red bar touches the blue line in the left corner of the Harmograph, he will cause a Beat Up, which will increase the size of the Heart Beat, which is the heart-shaped icon that can be seen in the lower-right corner.

Once the player has executed enough Beat Ups, and the Heart Beat has risen to its max size, a message displaying Purge Ready will appear over it. If at this time the player holds one of the four shoulder buttons (R1, R2, L1 or L2) and shakes the controller, a Purge will be executed. Once the Purge is executed, the Vanguards will all gain an elemental attack and resistance depending on which shoulder button was held when the control was shaken: The party will also gain a bonus from the Hyuma that was equipped on the shoulder button held by the player at that moment, and if the control shake was performed during a Beat Up, an animation will play out if the player has the Purge Movies enabled. Said animation can be longer or shorter depending on it the Purge executed was a single one, or a Multi-Purge. However, it has to be noted that once one element has been Purged, the shoulder button corresponding to it will be disabled until the Song Magic is released or the battle ends.
 * R1: Adds Fire attack & resistance.
 * R2: Adds Ice attack & resistance.
 * L1: Adds Wind attack & resistance.
 * L2: Adds Lightning attack & resistance.

In addition, there are also some other ways of gaining beats ups, such as executing Supermoves instead of normal attacks, performing Blowbacks, or simply, causing something that startles or surprises the Reyvateil, such as receiving a huge amount of damage from a single attack. Doing this last one will trigger an state called Scramble State, which will allow the player to Purge to the next level instantly. However, activating the Scramble State depends much on luck and its extremely risky, so it isn't wise to depend in it.

Finally, it's possible to Purge a max of four times at once, which is done by holding more than one shoulder button and shaking the controller. However, this requires clearing the Cosmospheres to a very high level, and since the Purge Ready indicator only serves to indicate when a single Purge is ready, the player will have to use his own judgement to decide when it would be the appropriate time for doing it. A failed multi-Purge will cause the same effect as Purging without the consent of the Reyvateil.

Jamming & Purge Hindrances
Among the actions that the enemies can take to keep the Reyvateils from Purging, the most simple of them is walking into the Heroine Field. Once they get into it, the Reyvateil won't be able to keep concetrated in her song, causing the Burst Gauge to severely slow down, the HP of the Reyvateil to slowly go down, and disabling completely further Purging. Luckily, it can be easily solved by performing a Blowback, which will push the enemy away from the Reyvateil.

However, there is a worse kind of hindrance, which is the Jamming attacks. These attacks are shown by an enemy stopping dead on its tracks and being surrounded by a blue barrier, while a blue line appears in the Harmograph. At this time, the Burst Gauge will stop charging, and Purging will be disabled. If the player doesn't manage to break the barrier before the blue line touches the left border of the Harmograph, the enemy will execute a powerful stored attack, which in some circumstances could completely wipe out a full party.

Purge Requirements
To have access to Purging, Flipsphere and Multi-Purges, the player must have cleared the following Cosmosphere levels for the Reyvateils: Note: In Finnel's case, this means that you need to have complete her fake Cosmosphere, which consists from a fake Lv. 2 to a fake Lv. 5. Afterwards, you will have access to her true Lv. 2. Also, Tyria already has all of these capabilities accessable from the point in which she joins the party.
 * Level 2 Purging: Available from the start.
 * Level 3 Purging: Clear Lv. 1 Cosmosphere.
 * Level 4 Purging: Clear Lv. 2 Cosmosphere.
 * Level EX Purging (Flipsphere): Clear Lv. 3 Cosmosphere.
 * Double Purging: Clear Lv. 4 Cosmosphere.
 * Triple Purging: Clear Lv. 6 Cosmosphere.