Synchronization

Synchronization chart from Neon Genesis Evangelion

Synchronization is a term used in the Evangelion series to measure the connection between a pilot and Evangelion unit.

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Despite having control sticks, Evangelion are entirely controlled by the pilots thoughts with the controls only being there to improve focus. As a result, pilots must synchronize to form the required mental bridge to activate and control their units. A frequently used measure of this connection is the sync rate, generally shown as waves the sync rate measures how connected the pilot and Evangelion unit are. The higher the rate is, the better the pilot is able to control the unit allowing for a higher combat potential.

This mental bridge doesn't just control the unit, it also ties the physical bodies of the pilot and Evangelion together which poses some risks to the pilot. Any damage sustained by the unit will be felt by the pilot with the amount of pain felt tied to the sync ratio (for example, if an Eva's arm is broken, then the pilot's arm will feel like it has been broken as well). Normally, this pain is just mental however at extremely high levels of synchronization it is possible for the pilot to sustain physical injuries as well.

The Synchronization chart in Rebuild of Evangelion.

Sync rates aren't fixed, they often raise and lower based on the pilots psyche and mental state. In the worst case, rates can fall so much the pilot loses the ability synchronize. Because of how important high levels of synchronization are, various technologies including plugsuits and interface headsets were developed in order to improve rates. While the the pilots ability and mental state determines the upper limit to their sync rate, NERV operators seemingly have some control over the rates. Whether they are limited to cutting off synchronization entirely or have more fine control over rates within a range is unclear.

Initialization

In order for an Evangelion to activate, it must first be initialized, a process which involves synchronizing and establishing a proper connection with its pilot. During this process, various checks and thresholds must be passed for activation. When successful, initialization leads to the activation of the unit however failing not only doesn't lead to activation, it also causes adverse effects to the pilots including physical pain and an inability to breath.

When initialization starts, the monitors within the Entry Plug flash various patterns and colours indicating the process is taking place.

First initialization stage.

Second initialization stage.

Third initialization stage.

Fourth initialization stage.

Plug Depth

Shinji entering a negative plug depth in Rebuild of Evangelion 2.0

The plug depth is a reflection of how high a pilots sync rate is, when rates are high the depth increases. While generally, high levels of synchronization are seen as positive and pilots and scientists strive to improve them, there's a point where it crosses from beneficial to dangerous. At a certain point, the mental damage the pilot sustains when their unit is damaged becomes physical however past even that, the pilot begins to lose their humanity as their physical form dissipates into the LCL contained within the plug. The sync rate required for such an occurrence is unknown however it is above 400%.

Sync Rate Testing

Deep synchronization testing from Neon Genesis Evangelion

As a part of the effort to continually develop the pilots and the equipment they use, the pilots sync rates are frequently tested during deep synchronization tests for change, ideally improvement, using special plugs which are not inserted into Evangelion or Simulation Bodies depending on the type of test being conducted.

Syncrograph in Evangelion Thrice Upon a Time showing a synch rate of infinity between Shinji and Unit-01.

The scores from these tests varies however one notable result is seen in Rebuild of Evangelion 3.0 and Thrice Upon a time where Shinji seemingly has a sync rate of zero sync which is later revealed to actually be infinite. The exact meaning of this is unclear and no explanation for the implications of this rate is given.

Trivia

• Kaworu Nagisa claims he has the ability to freely control his sync rate with Evangelion Unit-02. This is because the soul of Adam resides within him and unit-02 is born from Adam.
• While it is implied in Neon Genesis Evangelion that the sync rate indicated the pilots connection to the residing soul within the Evangelion, in the Rebuild of Evangelion series this likely isn't the case as pilots frequently change the Evangelion they are piloting while maintaining their rates which suggest synchronization works entirely differently in the rebuild series.