"Perfect Memorization" (完全記憶能力 Kanzen Kioku Nōryoku?) is the fourth episode of the first season of the Toaru Majutsu no Index anime series. It was first broadcast on October 25, 2008, and was directed by Kobayashi Kousuke and written by Akahoshi Masanao. Nishikiori Hiroshi returns to storyboard the episode along with Nakumura Noriyoshi.
Stiyl is not alone who is in the task of following Index, for a magician woman with a longsword, Kanzaki Kaori searchers for her as well. Touma is cut down with the overwhelming power of her sword technique. Before Kaori kills him, she questions the reasons why Touma is "protecting" Index, but Touma has none of it, and tries to resist her despite being worn out. Thinking Kaori manipulates magic, Touma tries to contend against her but is felled. In his faint consciousness, he discovers that she never intended to kill Index in the first place. Touma is hit with thoughts and questions. Empty wishes, and unexpected facts begin pouring from Kaori's mouth as Touma's eyes slowly shuts. Index has a checkered destiny. What kind of tragedy falls upon someone who has perfect memory?
Touma finds he is alone in a formerly busy intersection, when a mysterious girl wielding a nodachi introduces herself as Kanzaki Kaori and states the reason why there are no people, as a runic barrier has removed the people from the area. She mentions that she'd rather not mention her other name – her magic name, and requests Touma to hand Index over before she does so. Touma asks what happens if he refuses, to which Kaori demonstrates, by showing-off her power and cutting-off one of the blades of a wind turbine. Kaori repeats to Touma that she wishes to secure Index, however Touma answers to her that he has no reason to give up. This dismays Kaori and demonstrates a powerful attack on Touma, ruining the pavement of the road they are on. Kaori explains that the attack that she used can kill a person seven times in a split second, which she calls Nanasen.
Kaori tells Touma that she knows that his right hand can cancel magic, but states that as long as his right hand cannot touch something magical then he cannot cancel it. Touma charges towards Kaori, however, she uses her Nanasen and repels him. Touma tries to get up once more, which surprises Kaori and attacks Touma again with Nanasen. Touma charges through her attack and tries to cancel it, however, he realizes that it is not disappearing and injures his arm. He notices that there are ultra-thin wires that surround them, and she manoeuvres it using her katana and realizes that she is not using magic. Kaori asks Touma to not provoke her in envoking her magic name. Touma is unperturbed and provokes Kaori to attack him with Nanasen again. Touma tries to grab one of the wires which forces Kaori to hit him with the scabbard of her sword and the kicking him to the ground.
On the ground, Touma asks her why she did not kill him yet, even though she could've easily done so already. Touma states that he is simply a weak person trying desperately to protect a girl, and states that he and the magicians are different, as they are powerful enough to protect whoever the want to protect, and asks Kaori why this is the path they are taking. Kaori answers that they have no choice, and reveals that she is from the same church as Index, Necessarius – which surprises Touma. Kaori tells him that Index was her friend and that she did not mean harm to her. She tells him that if they cannot secure Index, then Index will not be able to live.
She tells Touma that since Index has the ability to perfectly memorize anything, she cannot forget any unnecessary memories needed for her brain keep functioning. Touma asks why Index calls Kaori and Stiyl evil even when they are from the same church. Kaori replies that Index has no memory that they are members of the same church, and have concluded on her own that Kaori and Stiyl are after the 103,000 grimoires inside of her. Kaori states that Index did not lose her memory, but in fact was erased by them. Kaori states that if they didn't erase her memories then Index would've died. She states that since 85% of her brain has been used for the storage of grimoires only 15% of the brain is left for other functions, but because of the fact that she has perfect memorization, then the 15% remaining will keep on taking in more information, and eventually end Index.
Since there was no other way, Touma asks Kaori when the next memory erasure will take place; Kaori says that the next one will occur in three days. Kaori once again asks Touma to hand Index over, or else she will invoke her magic name. Kaori tells Touma that saving Index brings him no benefit at all, but Touma says that what they are doing is wrong.
Touma rebukes Kaori for giving up easily on Index, but she shouts at him that he does not understand their own feelings of presenting themselves as enemies to Index. She proceeds to attack Touma several times, while shouting how they tried to keep making memories with her even though she will always forget. Even then, Touma still states that they are wrong and states that they did not think about Index at all, and states that even if her memories of the year would be erased, they should have reassured her that there would always be happiness that awaits her regardless of her losing her memories. Touma asks Kaori if she is only protecting people because she has power or that she acquires power because she had something to protect. He continues to ask her why she is using such a power for, and why she is so incompetent with protecting someone even if she had that much power, before collapsing from his injuries.
With Kaori shaken because of Touma's speech, Stiyl returns and asks if she is finished, to which she simply nodded, and then Stiyl removes the barrier. Meanwhile, Mikoto and Kuroko come out of a store after some shopping and notice the blade that was cut from the wind turbine. Kuroko, as a member of Judgment, goes into action to investigate. While waiting for Kuroko, Mikoto notices Index in the crowd, seemingly searching for something.
Touma wakes up in the Tsukuyomi residence, being taken care of Index. However, Touma realizes that three days has gone by since he was attacked by Kaori, and realizes that Index still has her memories. Index however, feels miserable for not knowing that Touma has been fighting against magicians and being unable to save him from harm. Touma then says that he is okay with how Index has treated him, and that he dislike the look of Index when she speaks of magic (referring to John's Pen Mode). Index says that she dislike when she "wakes-up" like that as she feels that she becoming more and more machine like when she is that state. Index later tries to serve food for Touma – which she fails spectacularly – before being interrupted by someone at the door.
It is revealed that it is Kaori and Stiyl who are on the front door, and have arrived to take away Index. However, Index thinking that they would hurt Touma again offers herself to them and asks them to stop hurting Touma anymore.
By order of appearance
No new characters were introduced during this episode.
- Empty Area (a type of rune magic) - Stiyl Magnus
- Imagine Breaker (not named) - Kamijou Touma Level 0
- Nanasen (Seven flashes) - Kanzaki Kaori
- Robotic control ability (mentioned only)
No new locations were introduced during this episode.
- First appearance of Stiyl's new runic cards.
- The song Ippou Tsuukou, Accelerator's leitmotif, is played during Kaori's explanation regarding Index's perfect memory, despite Accelerator not appearing for another 6 episodes.
- Kaori's sword is called Shichiten Shichitou, which literally means "Seven Heaven Seven Swords"; while her attack is called Nanasen (七閃?), which literally means "Seven Flashes", which according to Kaori, can kill a person seven times in a split second. Also according to Kaori, what awaits someone after going through Nanasen is Yuisen, which literally means "The Only Ray", though it is unknown what this implies.
- Kaori states Stiyl was hurt when he pretended to be an enemy towards Index. This is connected to Kaori's statement to Stiyl during the previous episode that he was in the same position as Touma is in now in regards with Index.
- The sword that Kaori is carrying is called a nodachi.
- The runic marking that Stiyl used in his cards is ᛟ, which means "heritage, estate or possession".
- When Touma is first kicked on to the ground by Kaori, his injuries disappear.
- The scene where grimoires are spinning around Index is reused in this episode, except Touma and Kaori are the characters instead of Index.
- Kaori mentions that Index had friends, family and lovers. We know that both Kaori and Stiyl were friends of Index prior to her memory lost, but we do not know who are the other people Index was close with before her memory lost.
- How did the church come-up with the 85% brain requirement for the grimoires?
- Kaori: "I would rather not mention my other name." -said to Touma, referring to her magic name.
- Kaori: "Isn't it quite enough? I don't believe you have any reason to be fighting this much for her." -said to Touma after kicking him to the ground.
- Touma: "This is wrong. Like this has anything to do with whether she remembers me or not...If you don't get it, then let me tell you why. Because I'm Index's friend! I've always been her friend, and I always will be! Even if wasn't written in the Bible, at least this is true!" -said to Kaori.
- Touma: " I knew something was weird. If it's as simple as her forgetting things, all you need to do is explain everything and clear the misunderstanding. Why do you leave it as a misunderstanding? Why do you chase after her as an enemy? How dare you just give up one her like that!" -said to Kaori, referring to how they opted to become Index's enemies instead of trying to clear-up the misunderstanding.
- Kaori: "We created memories, and so that she didn't forget them, we made a single promise with her, and we gave her a diary and album for her to carry inside her heart! And yet...it didn't work... Even when we went back and made more memories with her, no matter how many times we repeated that...memories of her family, friends, lovers...they were all reset to zero...We couldn't handle it anymore...We couldn't bear to see her smile anymore! " -said to Touma while beating him up.
- Touma: "That's wrong. That's your own bullshit logic. You didn't think for Index's sake a single moment. Don't blame your own gutlessness on Index! If you're so scared of seeing her lose one year's worth of memories...If you just give her more blessed memories the next year...If she knows there's happiness waiting for her the year after to let her conquer the fear of losing this year's memories, then no one needs to run away anymore! Isn't that all there is to this?" -a rebuttal to Kaori's statement.
- Touma: "Are you protecting people just because you have power? No, right? That's not how it is, right?! You acquired power because you have something you want to protect, right? Why did you acquire power? Who did you want to protect with those hands? Then what the hell are you doing here?! With that much power, with such a versatile power, why are you so incompetent?" -a continuation of Touma's rebuttal to Kaori's statement.
- Index: "I didn't know of anything. Komoe said that you were lying unconscous in the middle of the road. Komoe was also the one that carried your beaten body back to the apartment. I didn't realize anything. I didn't think at all that you were fighting against other magicians. I...I... couldn't save you..." -said to Touma.
- Index: "Please, I beg you, please. Please, don't hurt Touma anymore!" -said to Kaori and Stiyl.