The Alster bottle post mystery

Eight bottle post finds in Hamburg form one of the most exciting crypto mysteries I have reported on this blog so far. Will the mystery finally be solved this year?

Deutsche Version

It all started in October 2016, when Dominique Eggerstedt from Hamburg informed me about a coded message in a bottle she had found in the Isebekkanal, which is connected to the Außenalster. After that, in the course of three years, other readers informed me about similar finds in the same area.

In the meantime I know of eight cryptograms of messages in bottles. Still I have not the slightest idea what is behind it.

After almost every blog article I published on this topic, I informed various newspapers and radio stations in Hamburg. Unfortunately, none of these media jumped on the story. Perhaps it was because my articles were written in English. Or the responsible editors thought the whole thing was a joke staged by us.

So today, I’m going to try it with a German-language article about the Alster-Flaschenpost riddle. Furthermore, I explicitly assure that I did not create this message-in-a-bottle series myself or was involved in its creation in any way. Everything I know about it, I have published on this blog.

Another occasion for this article is a webinar talk on unsolved ciphers that I will be giving with Elonka Dunin (co-author of my current book Codebreaking: A Practical Guide) at the National Museum of Computing on January 28, 2021. The Alster bottle mail puzzle will be a topic in it.

The map below shows where the eight bottles were found:

Quelle/Source: Schmeh

My guess is that all the bottles were thrown into the water about where bottles 5, 6, 7 and 8 were found. That is where the Kaiser-Friedrich-Ufer (Kaifu) is located. Has any reader ever been there? Are there any places there from which something can be inconspicuously thrown into the water?


Bottle post 1

In October 2016, Dominique Eggerstedt found the first message in a bottle in the Isebek Canal.


Quelle/Source: Dominique Eggerstedt


Quelle/Source: Dominique Eggerstedt

Like all the following messages, this one consists of meaningful words (GIRL, GIRL, …), seemingly meaningless letters or numbers, and some symbols.


Bottle post 2

On January 24, 2017, a similar message was discovered in the Outer Alster, near the Kajüte restaurant (thanks to Alex Vladi for the tip).


Quelle/Source: Facebook


Bottle post 3

In April 2017, Tuncel Biyikli informed me about another message in a bottle of this kind. He found it on the eastern shore of the Outer Alster.


Quelle/Source: Tuncel Biyikli


Quelle/Source: Tuncel Biyikli

Meaningful words to see this mall include GIRL, STORM ORDER, and HIGH DANGER.

Bottle post 4

In September 2017, Hans von Jagow sent me a photo of another message in a bottle. He saw it floating on the water while rowing near the Krugkoppelbrücke.


Quelle/Source: Hans von Jagow

Among other things, you can recognize the words UBOATS and THE GREAT.


Bottle post 5

In May 2018, Katrin Reischert informed me about a message in a bottle she had found in the Isebek Canal a year earlier.


Quelle/Source: Katrin Reischert

QUICKBOOT, POSTFINANCE and GIRLS can be recognized in it.


Bottle post 6

In July 2018 I received another mail from Katrin Reischert. She had discovered another message in a bottle in the Isebekkanal.


Quelle/Source: Katrin Reischert


Quelle/Source: Katrin Reischert

As you can see, this message was in a plastic Coca-Cola bottle. The bottle mailings known up to that point were contained in small glass bottles like those used for spirits. The label of the Coke bottle is still present, while the labels of the glass bottles apparently came off in the water.


Bottle post 7

In August 2019, Christina Stacke sent me photos of not one but two bottle post finds. The following three pictures show one of them:

Quelle/Source: Christina Stacke

Quelle/Source: Christina Stacke

Quelle/Source: Christina Stacke

German words can be recognized here as well: ABSOLUT, UHRZEIT, BETREFF.

Bottle post 8

Message in a bottle number 8 is the last one that has surfaced so far. It is the second find of Christina Stacke.

Quelle/Source: Christina Stacke

Quelle/Source: Christina Stacke

The many graphic symbols are striking.


What’s behind it?

First of all, I assume that there are significantly more messages in bottles of this kind. If a reader has found one, please let me know (with place and time of finding). As far as I can judge, all messages were written with the same handwriting. So we are probably dealing with a “lone perpetrator”.

I don’t know if the cryptograms can be deciphered. The many excellent code breakers among my readers have unfortunately had no success in this regard so far.

Even more difficult is the question what purpose these bottle mailings should serve. It would be exciting, of course, if spies or criminals had communicated in this way. More likely, however, is one of the following scenarios:

  • Alternate Reality Game (ARG): ARGs typically begin by sending messages (e.g., letters) to selected individuals. These messages typically contain a call to action (e.g., “We need your help to save the world, call me on 01234/567890”). While I can well imagine the organizers of an ARG using messages in a bottle to launch their game, none of the messages found so far contain a call to anything. Or did the messages in a bottle play a role in a later phase of an ARG, when instructions were already known how to interpret them?
  • Geocaching: Crypto puzzles play a certain role in geocaching. Is this also the case here? Rather not. In any case, I can’t see how the various messages fit into a geocaching scenario. At least, finding a message in a bottle with GPS coordinates doesn’t make sense.
  • Kunst: A few years ago, about 20 encrypted notes were found at a university in Canada. In 2014, it became known that these messages had been created by a local artist. The crypto-mystery thus turned out to be a performance art project. It is, of course, possible that the Alster bottle post mystery also came about in this way.
  • Scherz: And finally, it is of course also possible that someone here has allowed himself a joke. If that is the case, the person responsible could slowly get in touch.

Can any readers say more about this puzzle?

If you want to add a comment, you need to add it to the German version here.

Further reading: Kaliningrad’s second mystery: Who can break this encrypted bottle post?


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