<p>While not impossible to open without tearing, and requiring cuts as well as folds (which disqualifies the method as origami to an origami purist), there is a form of letterlocking that involves cutting a thin strip from the blank margin of the letter, folding the letter, and then punching holes through the letter with an awl, and threading the strip through the holes in an interlocking knot-like pattern, which would make it very difficult to open the letter without tearing the thin delicate strip of paper.</p>

<p>See: <a href="https://vimeo.com/189348055" rel="noreferrer">https://vimeo.com/189348055</a></p>

<p><a href="http://letterlocking.org/categories" rel="noreferrer">http://letterlocking.org/categories</a> states that this blank margin method of letterlocking was "used by Queen Elizabeth I of England, Mary Queen of Scots, Catherine DeMedici, and many others."</p>

CC BY-SA 4.0
2018-06-19T23:29:02.217Z
2018-06-19T23:29:02.217Z
inkista
<p>So I may have stumbled onto a lead while doing some unrelated folding. This method isn't impossible to unfold without tearing, but it requires a fair bit of force (or an understanding of how it was folded) to do. Also, as far as I've been able to test, it's not possible to fold the letter back up in the same way once it's been unfolded, so if you've agreed on this method ahead of time with the recipient it serves a similar anti-tamper purpose as a wax seal, perhaps somewhat less secure but requiring no wax. Finally, it's very fast and simple to do. Here's the method:</p>

<ol>
<li>Start with your letter
<a href="https://i.sstatic.net/kQoiB.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/kQoiB.jpg" alt="Shhh! "></a></li>
<li>Fold it into roughly 3rds. It's not important that it be exactly 3rds but it <em>is</em> important that it's square, i.e. that the two folds are parallel with each other and perpendicular to the base, or as close as possible
<a href="https://i.sstatic.net/E7MMn.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/E7MMn.jpg" alt="Folded into 3rds"></a></li>
<li>Pinch one end of the paper to open up a "tunnel" at that end
<a href="https://i.sstatic.net/sbsPB.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/sbsPB.jpg" alt="Paper &quot;tunnel&quot;"></a></li>
<li>Push the other end of the paper into the tunnel. <em>Don't</em> crease any of the folds yet!
<a href="https://i.sstatic.net/5nqE8.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/5nqE8.jpg" alt="Into the paper tunnel"></a></li>
<li>This is the tricky part: push the free end of the paper as far into the tunnel as possible. This gets increasingly difficult the further you go due to the friction. I've found the it works best with more sturdy papers (printer paper does a fair job), and sturdier paper is harder to unlock. With the flimsy notebook page I used for this demonstration, I got the paper less than a 3rd of the way in
<a href="https://i.sstatic.net/LgAou.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/LgAou.jpg" alt="Shove it in there"></a></li>
<li>Now find the place where the paper ends inside the tunnel. Move up a little bit so you have a centimeter or so on both sides of where you're about to cease, and crease <em>hard</em>. This is the locking fold. Essentially you're forming this shape, but with the free end tucked inside the letter:
<a href="https://i.sstatic.net/iGHwe.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/iGHwe.jpg" alt="Essential locking fold"></a></li>
<li>Crease the other side so your paper lays flat and you're done!</li>
</ol>

<p>Like I said, this isn't perfect. You can definitely unfold the letter without tearing it, but I think this general idea (hidden folds inside the paper structure that are creased <em>after</em> tucking) has promise. I'll be playing around with this idea some more, and I'll update you all if I find a more secure method.</p>

CC BY-SA 4.0
2018-06-26T19:15:03.763Z
2018-06-26T19:15:03.763Z
realityChemist
<p>In Patrick Rothfuss' novel <em>The Wise Man's Fear</em>, the main character briefly mentions that he has a way of folding a letter to be its own envelope in such a way that it is not possible to reopen the envelope/letter without tearing it, giving a method of secure communication without sealing wax or similar. Does such a folding method actually exist?</p>

<p>I've done some experimenting myself, and some searching online, but the closest I've found are envelope designs that don't need tape/glue to stay closed. Nothing I've found has the key property of being impossible (or at least very difficult) to unfold again without tearing.</p>

CC BY-SA 4.0
2018-06-27T15:08:23.123Z
Sounds like a myth, but hold tight and maybe someone will eventually find this question and provide an interesting answer.  I have hopes for an answer that involves very delicate paper, and complicated folds that would tear such delicate paper.
New Alexandria
<paper><origami>
Irreversible Origami Envelope
realityChemist
# Irreversible Origami Envelope

(Asked by: username_0 on 2018-06-18)

In Patrick Rothfuss' novel *The Wise Man's Fear*, the main character briefly mentions that he has a way of folding a letter to be its own envelope in such a way that it is not possible to reopen the envelope/letter without tearing it, giving a method of secure communication without sealing wax or similar. Does such a folding method actually exist?

I've done some experimenting myself, and some searching online, but the closest I've found are envelope designs that don't need tape/glue to stay closed. Nothing I've found has the key property of being impossible (or at least very difficult) to unfold again without tearing.

**Tags:** paper, origami

> **Comments:**
> **username_1**: Sounds like a myth, but hold tight and maybe someone will eventually find this question and provide an interesting answer.  I have hopes for an answer that involves very delicate paper, and complicated folds that would tear such delicate paper.  

---

## 2 answers

### Answer by username_2 on 2018-06-19. Score: 7

While not impossible to open without tearing, and requiring cuts as well as folds (which disqualifies the method as origami to an origami purist), there is a form of letterlocking that involves cutting a thin strip from the blank margin of the letter, folding the letter, and then punching holes through the letter with an awl, and threading the strip through the holes in an interlocking knot-like pattern, which would make it very difficult to open the letter without tearing the thin delicate strip of paper.

See: <https://vimeo.com/189348055>

<http://letterlocking.org/categories> states that this blank margin method of letterlocking was "used by Queen Elizabeth I of England, Mary Queen of Scots, Catherine DeMedici, and many others."


---

### Answer by username_0 on 2018-06-26. Score: 4

So I may have stumbled onto a lead while doing some unrelated folding. This method isn't impossible to unfold without tearing, but it requires a fair bit of force (or an understanding of how it was folded) to do. Also, as far as I've been able to test, it's not possible to fold the letter back up in the same way once it's been unfolded, so if you've agreed on this method ahead of time with the recipient it serves a similar anti-tamper purpose as a wax seal, perhaps somewhat less secure but requiring no wax. Finally, it's very fast and simple to do. Here's the method:

1. Start with your letter
   [![Shhh! ](https://i.sstatic.net/kQoiB.jpg)](https://i.sstatic.net/kQoiB.jpg)
2. Fold it into roughly 3rds. It's not important that it be exactly 3rds but it *is* important that it's square, i.e. that the two folds are parallel with each other and perpendicular to the base, or as close as possible
   [![Folded into 3rds](https://i.sstatic.net/E7MMn.jpg)](https://i.sstatic.net/E7MMn.jpg)
3. Pinch one end of the paper to open up a "tunnel" at that end
   [![Paper "tunnel"](https://i.sstatic.net/sbsPB.jpg)](https://i.sstatic.net/sbsPB.jpg)
4. Push the other end of the paper into the tunnel. *Don't* crease any of the folds yet!
   [![Into the paper tunnel](https://i.sstatic.net/5nqE8.jpg)](https://i.sstatic.net/5nqE8.jpg)
5. This is the tricky part: push the free end of the paper as far into the tunnel as possible. This gets increasingly difficult the further you go due to the friction. I've found the it works best with more sturdy papers (printer paper does a fair job), and sturdier paper is harder to unlock. With the flimsy notebook page I used for this demonstration, I got the paper less than a 3rd of the way in
   [![Shove it in there](https://i.sstatic.net/LgAou.jpg)](https://i.sstatic.net/LgAou.jpg)
6. Now find the place where the paper ends inside the tunnel. Move up a little bit so you have a centimeter or so on both sides of where you're about to cease, and crease *hard*. This is the locking fold. Essentially you're forming this shape, but with the free end tucked inside the letter:
   [![Essential locking fold](https://i.sstatic.net/iGHwe.jpg)](https://i.sstatic.net/iGHwe.jpg)
7. Crease the other side so your paper lays flat and you're done!

Like I said, this isn't perfect. You can definitely unfold the letter without tearing it, but I think this general idea (hidden folds inside the paper structure that are creased *after* tucking) has promise. I'll be playing around with this idea some more, and I'll update you all if I find a more secure method.


---

