How did humans learn how to kill Titans?

Question

In Attack on Titan, how did humans learn the Titans' weak spot? How was it that they learned how to kill Titans?

• Was it through experiments with live, captured Titans?

The only example I could think of where humans successfully captured live Titans and managed to get them within the walls was when they captured Sawney and Bean. But, during the time they had Sawney and Bean up until their untimely deaths, humans were already actively aware of the Titans' weak spots, which was the back of their necks (which could be cut/sliced/attacked).

I am rewatching Attack on Titan now and am currently on Episode 1. I may have overlooked something the first time I watched (hence I am rewatching it) but I am quite positive this might not have been answered.

So how exactly did humans learn/discover how to kill Titans? I still don't quite understand this. Manga answers are perfectly acceptable. ;)

Answer 1

Your question is partly answered in the 17th chapter of the Manga SHINGEKI NO KYOJIN - BEFORE THE FALL.

This answer is a SPOILER for anyone who hasn't read the manga after chapter 16.

In this chapter, Instructor Jorge recalls the last Survey Corps expedition before their dissolution, before the beginning of the current story. He recalls the tests done on the captured titan. These tests of theirs sealed with finding the weaknesses, if any, of the titans, by hacking into their bodies with weapons made of Iron Bamboo. They discovered that their lower part of the body (limbs), and the head wasn't their weakness. Then they were interrupted by the onset of other titans from the South and the West. Here, the chapter ends and as the next chapter hasn't been released yet, we don't know how they got to know about the weak point. What we do know is that Angel Altonnen killed Mammon (a titan) using The Device (a prototype of 3DMG) and discovered the weak point.

I will update the answer as soon as more information is revealed....

Answer 2

The titans can sometimes be killed with canons if they hit the weak spot. It would be reasonable to presume that while they could not kill enough with canons to due to the regeneration, they could see the occational fatality and pass the information on. Some inventive mind would then create a more efficient way to target that spot. I believe after the battle for Trost they specify how many are killed by canon. But don't have a means right now to look it up.

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Edit: In manga chapters killing titans by shooting them with shells is explicitly mentioned by Armin in the battle of Trost and in one of the diagrams discussing the different between grape shot and regular shot. In addition:

We learn there are individuals who erased memories of all other humans. It is very possible that nobles with more information about the origins of titans revealed this info to those with the erased memories while holding other information back.

Answer 3

Here's an updated answer to your question. Note that this will contain spoilers from the manga Shingeki no Kyojin: Before the Fall and I'm confident this is accurate as of Volume 14 of the mentioned manga, which was where I stopped reading. Also, the events in this manga occurred approximately 50-70 years before the breach in Shiganshina District in the main Shingeki no Kyojin manga.

Before the invention of the Vertical Maneuvering Equipment, the Survey Corps could only counter Titans using swords, rifles and bombs for close-combat and cannons for long-range. This was shown in Volume 2 of the manga. However, this was just a stopgap and the most it could do was delay the movements of or distract a Titan due to its fast regenerative abilities. The swords were initially made using a naturally-growing/wild plant called Iron Bamboo before it would be replaced with ultrahard steel after the final design of the Vertical Maneuvering Equipment was completed.

However,

Angel Aaltonen, a craftsman, with the help of his assistant, Corina, and another craftsman, Xenophon Harkimo, were able to come up with an early model of the maneuvering equipment. This was mostly shown in Volumes 10-11 of the manga as Angel's flashbacks. This equipment could only move vertically (upwards and downwards). Also, unlike the current maneuvering equipment which has a control grip at the handle of each sword, the control grip for the early model was in one hand while the other holds the sword.

How did they come up with this idea?

It was Corina who suggested on thinking up on a device that allows them to fight 'on equal terms' with Titans. So, the invention of the first maneuvering device happened, to make up for the height difference of a human and a Titan. But, during this time, they were still unaware of a Titan's 'weak spot.'

How, then, were they able to 'learn to kill' a Titan?

After Angel, Corina and Xenophon returned from the Industrial City where they made the first model of the maneuvering device, a Titan was able to get inside the gates of Wall Maria, which ate Corina. Angel, wanting revenge, first joined an expedition to attempt to capture a Titan and find its weaknesses. This almost ended in failure but with the death of his close friend, Sorum, who sacrificed himself by blowing up a Titan's head when he was about to be eaten, they witnessed how the Titan did not regenerate and die (they saw lots of smoke being emitted from the Titan's body before disappearing). They initially presumed that the weak point might be the head or somewhere in the throat and neck. To test this, another expedition was led in secret by the Survey Corps and this time, Angel himself was able to kill a Titan, the first human to do so using the early model of the maneuver device, but the credit was given to the then-captain of the Survey Corps, Jorge 'The Hero', despite Jorge himself not wanting to.

In Volume 6 Chapter 19,

Jorge mentioned that they were not sure of the exact location of the 'weak spot' but this was what he said: '..based on the way Angel delivered the killing blow, we can assume that it is somewhere on the back of the neck. Angel was able to confirm that it was not actually the throat, as we initially surmised..' Therefore, it was Angel who discovered the Titan's weakness but after this expedition, he would disappear for roughly a decade before being convinced by Sharle to go back and help finish the device.

In Volume 12,

during their journey back to the Industrial City in Xenophon's workshop, it was Sharle who suggested that the control grip be placed on a sword's handle. After Sharle's suggestion, it took them one month to finalize the Vertical Maneuver Equipment's design and build it. Thus, mankind's first weapon that can actually kill Titans was finally finished.

Answer 4

I am rewatching the anime currently, about half way through episode 5 there is a part in which Eren and others were in a class learning about titans. Their teacher started with "What little we know about their bodies , we learned from Recon corps most recent report "..and then he continues teaching them how are titans killed. I haven't read the manga so I don't know about what's mentioned in the manga.

Answer 5

During one of the first encounters, a cadet was inspecting the body and thought to slice the back open, he missed and accidently cut the nape, when the Titan died, he reported it to his superiors, so the nape was found, this is said in the manga, can't remember where, hope this helps.

Answer 6

In the OVA "Ilse's Journal" Hanji/Hange tries to convince Erwin to let her capture another Titan, which is first refused due to the many squad members who had to die for a previous capture. It is not mentioned when that happened, but it makes sense to assume that a previous capture helped in learning how to kill a Titan - unfortunately also requiring Hange/Hanji to capture another one...