How And Why To Create A Zettelkasten: A Guide In The Vein of Niklas Luhmann


The goal of this article is to present the generic form of the Zettelkasten (in English—slip-box) as invented by Luhmann himself, as well as why it works and some of the theory behind it. From here you can modify the system to fit your needs, although I recommend staying true to the process he laid out as much as possible.

Who is the slip-box for?

Broadly speaking, I think two main kinds of people will benefit from using this technique:

  1. People who want or need to write academic/non-fiction works; original contributions to a body of knowledge.
  2. People who are serious about learning for the long-term and growing their expertise and knowledge in a field, or perhaps several

As you can see, these two categories aren’t necessarily mutually exclusive from each other. While you may want to have a note-taking technique that better facilitates learning, you can’t be an academic or non-fiction writer without having the ability to learn new things. Chances are, if you do either of the two above, you already have a system for it. Why would you want to learn a whole new system? There are three reasons:

  1. The slip-box is entirely designed to produce written works.
  2. The slip-box follows the best-practice techniques that we know of for learning.
  3. The slip-box can help prevent confirmation bias, if used correctly.

What You’ll Need:

In order to use the slip-box as Luhmann did, you will need three or four things.

1. A way to take notes:

This can be paper and pencil/pen, or a text editor on a computer.

2. A reference management system:

This is where you store the bibliographical information of all the books, articles, web pages, and general sources of information you will be referring to in your slip-box. For this you’re going to want to let a computer program handle it. I personally use Zotero.

3. A slip-box:

This can either be a program, or an actual physical slip-box.

As far as digital goes, you could technically emulate Luhmann’s system with nothing more than a basic text editor and plain text files collected inside a singular folder, but thankfully we have some nice options to choose from when it comes to specialized programs. The program I am currently using is Hendrik Erz’s Zettlr. The program is fast, lightweight, and is designed to easily emulate the core features that Luhmann’s system had. Also a very powerful option that, unfortunately, has a language barrier, is Daniel Ludecke’s Zkn3. The program has been translated into English, but all the documentation pages rely on Google’s finicky translation of a whole page, and is cumbersome to navigate. Just be aware of this if you’re going to use this option. Also worth perusing is the list the guys at have created, a list of programs that have been tested for use with such a slip-box system.

For a physical slip-box you can use just about anything. I suggest making the notes on small index cards, or something of similar size; having large sheets of notebook paper could quickly become intractable. You can also store the notes anywhere you like, but something like a shoe box would be best to make it manageable.

4. A text editor:

If you’re going to write, you’re definitely going to want a word processor of some sort. You can use an editor like Microsoft Word or LibreOffice Writer, or just a simple text editor like Sublime Text 3, Gedit, or Notepad. It should be noted that Zotero has the feature to add citations directly into your Word or Writer document. Its pretty nifty and helps to speed up the writing process a little.

Luhmann’s Method

Luhmann’s method for the slip-box can be broken down into two parts:

  1. The features of his system
  2. The workflow of his system

We’ll begin with the features, and then cover the workflow in-depth.

I have identified 5 main features of Luhmann’s slip-box:

  1. Category-free notes
  2. Atomized ideas
  3. Note Sequences
  4. Links
  5. And an index

1. Category-Free Notes:

Chances are you take notes the way you did in school: categories are decided upon up-front. Notes are taken in a linear order on notebook-sized paper, and then the notes are filed away and kept separate from other notes from other classes, subjects, and topics. Math goes here, philosophy goes in this binder, and so on. They are often filed by class, or by year/semester, and then left on a shelf to gather dust. This is, of course, if your notes are lucky enough to be put on paper to begin with. Often notes are just highlights and underlines made inside the book itself, where, once you have finished with the book, they will likely never be touched again.

Using a category-first system, the more notes we take and add to our system the messier things get. Adding notes to a specific category just makes them harder to find later when you need them and further complicates things. What happens if old notes would belong to a better category? How do we decide what category to put a note in? The only real solution is to create another category or subcategory, which will just push the mess to a different level in our organization system. To make it all worse, there’s no real way for notes to interact with each other and form connections unless they’re in the same category (and even then, it’s not likely to happen). This is a terrible way to take notes, at least if we want to do something with these notes; like learn, make connections, and use them in our own writing.

Instead of deciding on a category and then putting notes in it, Luhmann flipped the whole process. He instead put all his notes in the same place and standardized them: each note got a number in the corner that would refer to it’s fixed position in the slip-box. He would also allow categories and topics to build bottom-up by forming them with the index, and it was flexible too. If a category or topic no longer fit, he could just make a new one.

2. Atomized Ideas:

Luhmann put only one idea/fact/comment/thought per note card and, as a restriction of his physical system, only used the front so he could read them later without taking them out of the slip-box. For example, if you wanted to add Newton’s laws to the slip-box, Newton’s first law would get a card, Newton’s second law would get it’s own card separate from the first, and so on.

3. Note Sequences

Instead of keeping with the linear order of numbers (1, 2, 3, … and so on) and being forced to add every new note to his slip-box at the very end, Luhmann instead came up with the idea of note sequences by alternating numbers and letters. Once he had a new permanent note written he would approach adding it to his system by looking for a related note. Maybe he already had notes on a topic, and this note would fit best behind a note he’d already written, or perhaps he wrote the permanent note as a follow-up to an already existing one.

If the note he was following up on was 35, and 36 was already taken, he would name the new note 35a. If he wanted to further branch out the note 35a, he would add a note named 35a1. Now he has two branches from 35. He can then add notes behind 35a, or 35a1; following up on the content in that note at will by adding a 35b or 35a2.

Below is a visualization of the process and an example of how Luhmann did it:


4. Links:

You can imagine these as hyperlinks on a Wikipedia page. These would be to the notes that either couldn’t have been part of a note sequence, or notes that are related and you can form a connection between in some way.

5. An Index

This is how Luhmann allowed topics to arise bottom-up. Dedicated notes would have nothing but links on them, and serve as an overview of a topic. He would then link from one of these overview notes to his master index. This master index allowed him to easily get back into a line of thinking, or a topic he was working on. With this index system, he could create new categories and topics on the fly, as well as combine notes from many different sources into a topic, and organize them in any manner he wanted.

As an example, if I’m reading a book, I like to collect all the links from that book in one note. I can then link that note to my master index so it won’t be lost and I can quickly get an overview of all the notes I’ve gathered from the book so far.

Here are two images to help you visualize how this indexing process works sourced from my own slip-box:

Luhmann’s Workflow:

The actual workflow of the system is incredibly simple.

When Luhmann would read a book, he would take notes on it, making sure to include bibliographical information and the page numbers of things he extracted. These would be his fleeting and literature notes. These would then become the basis for his permanent notes. The permanent note would then be filed into the slip-box, either as a note sequence following up on a specific note, or at the very end of the slip-box. The number/lettering system would be given, and then he would search for related notes to form links. The last step is that he would add a link to his index so he would be able to find it again later.

At this point you’re probably wondering what these terms mean, and exactly what kind of notes go into the slip-box. Let’s hit two birds with one stone.

The four types of notes you will take using this system:

1. Fleeting Notes

2. Literature Notes

3. Permanent Notes

4. Project Notes

1. Fleeting Notes:

These are notes for ideas that pop into your head, or thoughts you have while reading, and need to be written down before they are forgotten.

2. Literature Notes:

These consist of the notes we take on the text we’re actually reading, and include anything we don’t want to forget or might use in our thinking, learning, and writing. These notes can either be filed away in our reference management system or placed somewhere that we can retrieve it again should we need it.

How do we take literature notes? The short answer is, any way you want that’s conducive to the overall process. It doesn’t matter if you want to have an incredibly in-depth note-taking process with color-coded highlighters and pens, the only thing that matters is that these notes help you work to an understanding of the text, and they help you with the step that matters most—making the permanent notes. Luhmann himself took fairly short notes in the format of “on page x is such and such”, but being a multi-disciplinary expert as he was, we likely won’t be able to have such terse notes in the beginning, especially when learning a new subject. Literature notes are a form of deliberate practice, and as long as we stick with the process and push through the tough part of learning a new subject we will soon find our notes becoming more condensed and the ability to process texts on the subject much faster.

3. Permanent Notes:

These are the notes that you write for the slip-box. They are based on the literature and fleeting notes you have written in earlier stages. These are written with explicit references to the sources from which they were taken, and are written in your own words as-if you’re teaching it to someone else. The idea is that you need to be able to read and fully understand what’s on this note days, months, and possibly years from the time that you wrote it. It shouldn’t be a carbon-copy of whatever it is you’re reading. Luhmann himself wrote summarized excerpts; they were a translation from one context to another, while keeping the original meaning as closely as possible.

Having your notes in your own words is a critical step. It shows that you actually understand what you have read and allows you to read a permanent note you might have forgotten about and re-learn whatever is on it. It also helps you to actually make use of the idea on it, either when learning something new or writing something new.

4. Project Notes:

These are notes that are specific for a project that you are working on. They include:

  • Comments on your manuscript
  • Literature related to your project
  • outlines of your writing
  • Chunks of drafts
  • Reminders
  • To-do lists
  • The draft itself


It is of critical importance to keep these four kinds of notes separated. Anyone who has tried to make a commonplace book out of a simple notebook will attest to the difficulty of trying to retrieve your notes when the four types are all mixed up. Only the permanent notes go into the slip-box.

Let’s go a little bit further than that. What exactly do we take permanent notes on? Well, the answer is whatever we took literature and fleeting notes on; and what do we take literature notes on? Anything you might use in your thinking, learning, or writing, and don’t want to forget.

I feel as if the best way to illustrate this is with a short example of what I have in my slip-box. My note number 2 is a note sourced from the book, Sapiens: A Brief History Of Humankind, on his definition of religion. Following that note in the number 3 spot is a note on how he addressed objections to the definition. Looking at these two notes alone we can see that they can easily form links with new permanent notes being added and spark thinking. Should I choose to shift my reading and note-taking interests into the realms of religion I can see how the new notes I’ve taken on a different book support, compare, or perhaps contradict what he has written.

We should also consider what you wouldn’t put into the slip-box. I would say that things such as English vocabulary would be a poor fit. This doesn’t mean new technical terminology for a subject shouldn’t be added, these notes can be very useful and will often create many links to new concepts you learn. As you practice and use the system you will get a feel for how to atomize new information and decide what would be best left out, or stored somewhere else, like a spaced repetition program for vocabulary. Luhmann himself wrote that the slip-box can hold almost anything in it; the only real precondition is that it can make connections with the other permanent notes.

Theory Behind System:

If you recall, I cited three reasons for switching your system to the slip-box: It is a system that helps us write, learn, and combat confirmation bias. Now that we know how the system works, let’s see how it can help us accomplish each of these.

1. It’s a writing machine:

Broadly speaking, creating a written non-fiction work requires three (very large) steps:

1. Having our facts, sources, and arguments, all written out in some form

2. Organizing those notes into a linear draft

3. Editing that draft into a finished piece

The most difficult part of writing non-fiction is getting it all down on paper. Even if you happen to have it all in your head it will eventually need to be turned into notes of some kind on paper or a computer screen, and then organized into a draft.

You might agree that the hard part of writing is organizing all the ideas, but how does the slip-box improve on just taking standard notes for our writing projects? The answer is that the slip-box is something more than just an archive. It’s clear from Luhmann’s writing that he saw his slip-box as a critical communication partner he used to conduct his research. He didn’t take notes as most knowledge workers do, for the current project or book, but for a lifetime of writing, thinking, and learning.

If we follow his workflow, we have already taken notes on what interests us the most, and the notes are embedded in a web of links and already formed into sequences. This is simply the best-case scenario of the first phase above. If we have allowed topics to arise bottom-up instead of deciding on one ahead of time as the academic writing books suggest, thus wiring confirmation bias into our process, we are already in an incredibly good position to turn our notes into a linear draft.

2. It helps you learn for the long-term

When we use the slip-box we engage in the techniques most recommended to learn efficiently and effectively. We use elaboration when we make permanent notes by writing them in our own words and trying to understand the broader implications of the information. We retrieve old information when trying to form connections with a new note. We change up contexts and use variation when connecting the new notes to old, and retrieve information in spaced out intervals. Lastly, during that elaboration on the information, both old and new, it requires us to use recall and understand what we’re writing, or else we would just be copying.

3. It helps us fight confirmation bias

Instead of starting with a preconceived idea and finding confirming evidence (like most books on writing suggest), we flip the process by letting topics form from our reading, note-taking, and building a critical mass inside of the slip-box. Instead of looking for confirming facts, we gather anything relevant to the topic, regardless of what argument it supports. All that matters is that something adds to a discussion in the Zettelkasten, if it connects, or is open to connections.

Final Words:

My writing and research here is based on the phenomenal book by Sonke Ahrens ‘How To Take Smart Notes’, as well as the original writings of Luhmann, and some of the contributions to the dialogue around Luhmann’s Zettelkasten by Daniel Ludecke. I am eternally grateful for their tutelage, and I hope my writing was able to do them justice. Also, if you can read German, you can go online at this very moment and see Luhmann’s exact writing inside his system and how he did things. If not, you can at least get a visual overview of how he handled linking, note sequencing, and so on.

If anything in the above article was not clear, or confusing, drop me a comment down below and I’ll see if I can clarify it for you.

Happy note taking!


Ahrens, Sönke. 2017. How to Take Smart Notes. North Charleston, SC: CreateSpace.

Conferences, NEWCRAFTS. 2018. Sönke Ahrens – How to Take Smart Notes.

Duly Noted – Dr. Sönke Ahrens, Author, How to Take Smart Notes – Finding Efficiency in Note Takin… n.d. Accessed December 17, 2019.

Lüdecke, Daniel. 2017. “Introduction to Luhmann’s Zettelkasten thinking and Its Technical Implementation.”

Luhmann, Niklas. 1992. “Communicating with Slip Boxes by Niklas Luhmann.” 1992.

Schmidt, Johannes F. K. 2018. “Niklas Luhmann’s Card Index: The Fabrication of Serendipity.” Sociologica 12 (1): 53–60.

Tietze, Christian. 2015. “Different Kinds of Ties Between Notes.” Zettelkasten Method. November 17, 2015.

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