Synchronization refers to the process that connects a pilot and their Evangelion, allowing the pilot to activate and pilot the it. This process occurs while the pilot is inside the Entry Plug after the plug has been inserted through the back of the Evangelion's neck, although during harmonics tests, Test plugs and Simulation bodies are used along with the Evangelion. Upon synchronization, a neural connection is made between the pilot (and possibly the soul within) the Evangelion, allowing the pilot to not only move the Evangelion, but physically feel what the Evangelion feels. This form of feedback causes the pilot to also feel pain when pain is inflicted upon the Evangelion, and in extreme cases, physical manifestations of the pain can be seen. There are also other dangers when synchronized, such as mental trauma or mental contamination, and in extreme cases, the pilot's body can revert to LCL inside the entry plug, trapping their soul inside the Evangelion.
Synchronization usually follows in steps, monitored and controlled by the Nerv personnel, although it appears that synchronization can be initiated without external aid, at least in the case of Evangelion Unit-02, which is operated independent of Nerv by both Shinji Ikari and Asuka Langley Soryu in Episode 08. Shinji synchronizes independently in Episode 18 again.
- Man A: Roger. Inserting entry plug.
- Woman: Direct hydro-transmission system, connection prepared.
- Man A: Plug fixed in place.
- Man B: First stage connection initiated.
- Maya Ibuki: Filling the entry plug.
- Man A: Connecting main power.
- Maya Ibuki: Commencing secondary contacts. A-10 nerve connection, normal.
- Ritsuko: Set the thought configuration to Japanese. All preliminary contacts established.
- Maya Ibuki: Bi-directional circuits are open. Synchronization rate at 41.3%
Evangelion Unit-02's activation in Episode 08 reveals that synchronization is dependent upon the language in which the pilots think. Shinji thinks in Japanese, and Asuka in German, causing a system error and forcing Asuka to restart with the language set to Japanese. What language has to do with synchronization is not further explored or elaborated. Asuka's mother and the soul of Eva-02, Kyoko Zeppelin Soryu, was bilingual in German and Japanese and should have had no difficulty understanding both languages. This suggests that additional equipment within the Evangelion aids in synchronization as an intermediary (Possibly being bypassed during periods of extremely high synch rate or when the Eva goes berserk). Another possible instance of such a system being used is in Episode 03, where Eva-01's synaptic commands are looped for a short period.
Shinji synchronizing with Evangelion Unit-01 in Episode 01
It is believed that the Interface Headsets used by the pilots either are required or greatly enhance synchronization. These are always worn by the pilots within their entry plugs. Also of significance is the A-10 nerve connection which may indicate that the pilots are actually synchronizing with the souls within the Evangelion (the soul of the pilot's own mother) as much as with the Evangelion itself. In an interview with Yoshiyuki Sadamoto, he states that:
|“||I was watching the NHK [public TV channel] program "Brain and Heart" and learned about the existence of the A10 nerve, and I told Anno about the idea that popped into my head at that time. That was the idea where "the dead mother is inside the robot, which is operated by mental/psychical bonding with the child."||„|
In another interview :
|“||On the floor of the midbrain is the ventral segmental system, that neurobiologists call region A10. Cells soaked in dopamine, certain emotions are processed here: such as the thoughts of two lovers - or a parent and a child. And it is the synchronization of the threads and bundles of A10 that splice pilot and Eva together; to become one entity, to fight. In other words, the power of love drives this weapon of mass destruction.||„|
The Synchronization Rate, or just Synch Rate, refers to the degree of synchronization achieved; the higher the synch rate, the better the synchronization between pilot and Evangelion is. Presumably, higher synch rates result in better control but an increased risk in physical harm for the pilot. The synch rate, although ultimately limited by the pilot's own abilities, can be controlled (remotely) by the Nerv personnel like the synchronization process itself; Fuyutsuki gives the order to reduce Rei's synch rate with Eva-00 to sixty percent during the Bardiel attack.
It is possible for the synch rate, which is reported in the form of a percentage, to exceed 100%. In Episode 19, Shinji achieved an abnormally high 400% synch rate during the battle with Zeruel resulting in him disembodying into LCL within the entry plug.
|Eva-02's synch graph|
Eva-02's synchronization rate jumping in Episode 08. (The markings on the bottom go below zero)
"It's just a garbage dump."
- In Episode 01, Misato says that it took Rei seven months to synchronize with her Evangelion. This is most likely due to the fact that Unit 00 was a prototype and had to be fixed to fit her abnormal DNA.
- In Episode 01, Shinji's first time synchronizing with an Evangelion, Maya reported his synch rate at 41.3%.
- In Episode 08, Asuka is shocked when Kaji tells her of Shinji's high first time synch rate.
- In Episode 14 during the cross-synch tests between Rei and Shinji, Rei is reported to have nearly the same synch rate with Eva-01 as with Eva-00, however, Shinji's synch rate with Eva-00 is lower than with Eva-01.
- In Episode 16, Shinji exceeded Asuka's synch rate with their respective Evangelions, ousting Asuka from being the highest synch rate holder. Rei remained the lowest amongst the three.
- In Episode 22, Ritsuko says that the synch rate isn't affected by superficial physical conditions.
- By Episode 22, Asuka's synch rate had been dropping and reached a level just above the activation level. By Episode 23, her synch rate is at single digits (she could not move her Evangelion) and by Episode 24, it's zero. Kaworu's statement in Episode 24 that Eva-02's soul had shut itself away could explain why Asuka was barely able to synchronize with the Eva following Arael's attack. She recovers her ability to synchronize with Eva-02 during Episode 25'.
- Her final synchronization with the Eva appears to have been at an extremely high synch rate, lower than the border needed to dissolve her body but high enough for her to sustain actual physical damage from the Eva's wounds.
- In Episode 24, Misato says that Kaworu is able to arbitrarily set his synch rate to any level, which is theoretically impossible. Kaworu being the vessel of Adam's soul, is made of the same matter as the Evas and can control Eva-02 from outside the entry plug. He probably doesn't need to synchronize in the same way as a regular pilot.
- "Interview with Yoshiyuki Sadamoto in the Deluxe Edition of the artbook "Der Mond" in September 1999, translated by Bochan Bird
- Supplementary interview from volume 1 of Sadamoto's manga.