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

<p>This answer is a <strong>SPOILER</strong> for anyone who hasn't read the manga after chapter 16.</p>

<blockquote class="spoiler">
  <p> 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 <strong>Iron Bamboo</strong>. 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 <strong>The Device</strong> (a prototype of 3DMG) and discovered the weak point.</p>
</blockquote>

<p>I will update the answer as soon as more information is revealed....</p>

CC BY-SA 4.0
2018-07-28T19:17:32.573Z
Can you update your answer with what happened in the next chapter, if it's relevent?
YetAnotherRandomUser
CC BY-SA 4.0
2018-07-29T03:00:18.790Z
I wasn’t able to read much after this chapter, so I’ll try to update this in a couple of days.
Pratyush Manocha
CC BY-SA 3.0
2016-01-08T12:11:36.523Z
2016-01-08T12:11:36.523Z
Pratyush Manocha
<p>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.</p>

<hr>

<p>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:</p>

<blockquote class="spoiler">
  <p> 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.</p>
</blockquote>

CC BY-SA 3.0
2014-08-22T18:08:18.177Z
2015-03-24T19:40:53.300Z
2015-03-24T19:40:53.300Z
kaine
<p>Here's an updated answer to your question. Note that this will contain spoilers from the manga <strong>Shingeki no Kyojin: Before the Fall</strong> and I'm confident this is accurate as of <strong>Volume 14</strong> 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 <strong>Shingeki no Kyojin</strong> manga.</p>

<blockquote class="spoiler">
  <p>Before the invention of the <a href="https://attackontitan.fandom.com/wiki/Vertical_maneuvering_equipment" rel="nofollow noreferrer">Vertical Maneuvering Equipment</a>, the Survey Corps could only counter Titans using swords, rifles and bombs for close-combat and cannons for long-range. This was shown in <strong>Volume 2</strong> of the manga. However, <strong>this was just a stopgap and the most it could do was delay the movements of or distract a Titan</strong> due to its fast regenerative abilities. The swords were initially made using a naturally-growing/wild plant called <a href="https://attackontitan.fandom.com/wiki/Iron_bamboo_(Before_the_Fall_Manga)" rel="nofollow noreferrer">Iron Bamboo</a> before it would be replaced with <a href="https://attackontitan.fandom.com/wiki/Ultrahard_steel_(Before_the_Fall_Manga)" rel="nofollow noreferrer">ultrahard steel</a> after the final design of the Vertical Maneuvering Equipment was completed. <a href="https://i.sstatic.net/mhiTe.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/mhiTe.jpg" alt="enter image description here"></a></p>
</blockquote>

<p>However,</p>

<blockquote class="spoiler">
  <p> <a href="https://attackontitan.fandom.com/wiki/Angel_Aaltonen" rel="nofollow noreferrer">Angel Aaltonen</a>, a craftsman, with the help of his assistant, <a href="https://attackontitan.fandom.com/wiki/Corina_Ilmari" rel="nofollow noreferrer">Corina</a>, and another craftsman, <a href="https://attackontitan.fandom.com/wiki/Xenophon_Harkimo" rel="nofollow noreferrer">Xenophon Harkimo</a>, were able to come up with an early model of the maneuvering equipment. This was mostly shown in <strong>Volumes 10-11</strong> of the manga as Angel's flashbacks. <a href="https://i.sstatic.net/avIiR.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/avIiR.jpg" alt="enter image description here"></a> 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. <a href="https://i.sstatic.net/qACrV.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/qACrV.jpg" alt="enter image description here"></a> <a href="https://i.sstatic.net/3CllW.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/3CllW.jpg" alt="enter image description here"></a></p>
</blockquote>

<p><strong>How did they come up with this idea?</strong> </p>

<blockquote class="spoiler">
  <p>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, <strong>to make up for the height difference of a human and a Titan.</strong> But, during this time, they were still unaware of a Titan's 'weak spot.' <a href="https://i.sstatic.net/waNaT.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/waNaT.jpg" alt="enter image description here"></a></p>
</blockquote>

<p><strong>How, then, were they able to 'learn to kill' a Titan?</strong> </p>

<blockquote class="spoiler">
  <p>After Angel, Corina and Xenophon returned from the <a href="https://attackontitan.fandom.com/wiki/Industrial_City" rel="nofollow noreferrer">Industrial City</a> 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 <strong>an expedition to attempt to capture a Titan and find its weaknesses.</strong> This almost ended in failure but with the death of his close friend, <a href="https://attackontitan.fandom.com/wiki/Sorum_Hum%C3%A9" rel="nofollow noreferrer">Sorum</a>, 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). <strong>They initially presumed that the weak point might be the head or somewhere in the throat and neck.</strong> To test this, <strong>another expedition was led in secret by the Survey Corps</strong> 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, <a href="https://attackontitan.fandom.com/wiki/Jorge_Pikale" rel="nofollow noreferrer">Jorge 'The Hero'</a>, <a href="https://attackontitan.fandom.com/wiki/Jorge_Pikale#Trivia" rel="nofollow noreferrer">despite Jorge himself not wanting to</a>. <a href="https://i.sstatic.net/xxI3L.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/xxI3L.jpg" alt="enter image description here"></a> </p>
</blockquote>

<p>In <strong>Volume 6 Chapter 19</strong>, </p>

<blockquote class="spoiler">
  <p>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, <strong>it was Angel who discovered the Titan's weakness</strong> but after this expedition, he would disappear for roughly a decade before being convinced by <a href="https://attackontitan.fandom.com/wiki/Sharle_Inocencio" rel="nofollow noreferrer">Sharle</a> to go back and help finish the device. </p>
</blockquote>

<p>In <strong>Volume 12</strong>, </p>

<blockquote class="spoiler">
  <p>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. <a href="https://i.sstatic.net/zcyQW.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/zcyQW.jpg" alt="enter image description here"></a> 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. </p>
</blockquote>

CC BY-SA 4.0
2018-11-14T10:31:51.890Z
To the one who retracted his upvote, I don't mind but I would greatly appreciate if you mention why (maybe errors, wrong information, confusing info, etc.) so that I can improve this post further. Thank you so much! :)
W. Are
CC BY-SA 4.0
2018-11-13T14:18:56.543Z
2018-11-14T02:40:38.737Z
2018-11-14T02:40:38.737Z
W. Are
<p>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.</p>

CC BY-SA 3.0
2016-05-31T21:48:13.037Z
2016-05-31T21:48:13.037Z
Aditi
<p>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.</p>

CC BY-SA 3.0
2016-10-09T18:43:28.540Z
2016-10-09T18:43:28.540Z
AOTfan1
<p>In the OVA "<a href="http://attackontitan.wikia.com/wiki/Ilse%27s_Notebook:_Record_of_a_Fallen_Soldier" rel="nofollow noreferrer">Ilse's Journal</a>" Hanji/Hange tries to convince Erwin to let her capture <em>another</em> Titan, which is first refused due to the many squad members who had to die for a previous capture. It is not mentioned when <em>that</em> 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...</p>

CC BY-SA 3.0
2017-01-31T07:09:30.010Z
2017-01-31T07:09:30.010Z
Zommuter
<p>In <strong>Attack on Titan</strong>, how did humans learn the Titans' weak spot? How was it that they learned how to kill Titans?</p>

<ul>
<li>Was it through experiments with live, captured Titans?</li>
</ul>

<p>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).</p>

<p>I am rewatching <strong>Attack on Titan</strong> now and am currently on <strong>Episode 1</strong>. 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.</p>

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

CC BY-SA 3.0
2014-08-21T07:50:27.387Z
That's a very good question. I don't think it was explained (yet), but it's likely as you've described, through experimentation with captured titans.
Madara's Ghost
CC BY-SA 3.0
2014-08-21T08:15:22.863Z
I'd assume that it was due to some combination of luck and experimentation, but I haven't read the manga and this definitely wasn't in the anime.
Maroon
CC BY-SA 3.0
2014-08-21T14:54:17.103Z
I have read manga until a while ago, and I can be sure that it wasn't mention how the human knows the titans' weak point. It is only mentioned as knowledge taught in school.
nhahtdh
CC BY-SA 3.0
2014-09-07T10:06:47.897Z
The answer is in the manga "Shingeki no Kyojin Before the Fall" about seventy years before the actual story. I think it was discovered by the same person who invented the 3dmg.
But I still can't give a good answer since I only got up to chapter 8.
Eemduhuym Thenelt
<attack-on-titan>
How did humans learn how to kill Titans?
# How did humans learn how to kill Titans?
Posted by: username_0 on 2014-08-21
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. ;)
**Tags:** attack-on-titan
> **Comments:**
> **username_1**: That's a very good question. I don't think it was explained (yet), but it's likely as you've described, through experimentation with captured titans.  
> **username_2**: I'd assume that it was due to some combination of luck and experimentation, but I haven't read the manga and this definitely wasn't in the anime.  
> **username_3**: I have read manga until a while ago, and I can be sure that it wasn't mention how the human knows the titans' weak point. It is only mentioned as knowledge taught in school.  
> **username_4**: The answer is in the manga "Shingeki no Kyojin Before the Fall" about seventy years before the actual story. I think it was discovered by the same person who invented the 3dmg.
But I still can't give a good answer since I only got up to chapter 8.  
---
## 6 answers
### Answer by username_5 on 2016-01-08. Score: 10
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....
> **Comments:**
> **username_6** (2018-07-28): Can you update your answer with what happened in the next chapter, if it's relevent?  
> **username_5** (2018-07-29): I wasn’t able to read much after this chapter, so I’ll try to update this in a couple of days.  
---
### Answer by username_7 on 2014-08-22. Score: 6
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.

---

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 by username_8 on 2018-11-13. Score: 2
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](https://attackontitan.fandom.com/wiki/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](https://attackontitan.fandom.com/wiki/Iron_bamboo_(Before_the_Fall_Manga)) before it would be replaced with [ultrahard steel](https://attackontitan.fandom.com/wiki/Ultrahard_steel_(Before_the_Fall_Manga)) after the final design of the Vertical Maneuvering Equipment was completed. [![enter image description here](https://i.sstatic.net/mhiTe.jpg)](https://i.sstatic.net/mhiTe.jpg)

However,

> [Angel Aaltonen](https://attackontitan.fandom.com/wiki/Angel_Aaltonen), a craftsman, with the help of his assistant, [Corina](https://attackontitan.fandom.com/wiki/Corina_Ilmari), and another craftsman, [Xenophon Harkimo](https://attackontitan.fandom.com/wiki/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. [![enter image description here](https://i.sstatic.net/avIiR.jpg)](https://i.sstatic.net/avIiR.jpg) 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. [![enter image description here](https://i.sstatic.net/qACrV.jpg)](https://i.sstatic.net/qACrV.jpg) [![enter image description here](https://i.sstatic.net/3CllW.jpg)](https://i.sstatic.net/3CllW.jpg)

**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.' [![enter image description here](https://i.sstatic.net/waNaT.jpg)](https://i.sstatic.net/waNaT.jpg)

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

> After Angel, Corina and Xenophon returned from the [Industrial City](https://attackontitan.fandom.com/wiki/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](https://attackontitan.fandom.com/wiki/Sorum_Hum%C3%A9), 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'](https://attackontitan.fandom.com/wiki/Jorge_Pikale), [despite Jorge himself not wanting to](https://attackontitan.fandom.com/wiki/Jorge_Pikale#Trivia). [![enter image description here](https://i.sstatic.net/xxI3L.jpg)](https://i.sstatic.net/xxI3L.jpg)

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](https://attackontitan.fandom.com/wiki/Sharle_Inocencio) 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. [![enter image description here](https://i.sstatic.net/zcyQW.jpg)](https://i.sstatic.net/zcyQW.jpg) 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.
> **Comments:**
> **username_8** (2018-11-14): To the one who retracted his upvote, I don't mind but I would greatly appreciate if you mention why (maybe errors, wrong information, confusing info, etc.) so that I can improve this post further. Thank you so much! :)  
---
### Answer by username_9 on 2016-05-31. Score: 1
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 by username_10 on 2016-10-09. Score: 0
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 by username_11 on 2017-01-31. Score: 0
In the OVA "[Ilse's Journal](http://attackontitan.wikia.com/wiki/Ilse%27s_Notebook:_Record_of_a_Fallen_Soldier)" 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...
---
