Pronounced: Zet‧tel‧kas‧ten

German word for box of notes

📔 Introduction

The Zettelkasten is a system of note-taking and personal knowledge management used in research and study. This method was invented in the 1500s, and was later popularized by Niklas Luhmann (1927–1998), a researcher and sociologist. Luhmann built up a Zettelkasten of some 90,000 index cards for his research, and credited it for enabling his extraordinarily prolific writing, including over 70 books and 400 scholarly articles 🤯

A Zettelkasten is a personal tool for thinking and writing. It has hypertextual features to make a web of thought possible. The difference to other systems is that you create a web of thoughts instead of notes of arbitrary size and form, and emphasize connection, not a collection.

Sascha, Zettelkasten Coach

🧠 What do Believers say?

  • Improve the connectivity of ideas. The hypertextual nature of the Zettelkasten enables you to connect ideas. These connections make new insights possible. Insights don’t happen in a vacuum. They are the result of making new connections.
  • Create future value. Even if you don’t use any of your notes for a project you’re working on at the moment, you prepare the knowledge for future projects. Write to your future self.
  • Tackle more complex problems. It is very difficult to keep all the balls in the air when you juggle complex problems. The Zettelkasten Method allows you to concentrate on a small part of the problem and after that take a step back and look at it with a bird's eye view.
  • Believers insist that Zettelkasten makes writing easier, more coherent, smoother and more convincing. One of the main problems in writing and thinking is our limited capacity to follow one line of thought for a long period of time. Just think of meditation. It is even difficult to focus on a simple thing like breathing for a couple of minutes. Imagine how difficult it is to think about one issue for weeks and months to write a thesis. The Zettelkasten will hold your thoughts alive and help you to hold onto them.

    🗃️ So how did it work before computers?

    The Fixed Address of Each Note

    Luhmann’s numbering system allowed to make sequences and intersperse notes between adjacent notes through adding another character to the end

    💡 Core Principles

    Principle #1: Hypertextual 🔗

    The difference between regular note-taking systems and a Zettelkasten is the emphasis on forming relationships. To become a hypertext, a Zettelkasten requires multiple texts, or notes, that you can connect via hyperlinks. We call an individual note a Zettel. Zettel is the German word for “paper slip”. They are the smallest building blocks of the Zettelkasten.

    Principle #2: Atomicity ⚛️

    Each Zettel only contains one unit of knowledge (one thought)and one only. These units are the atoms to which the principle of atomicity refers. In contrast:

  • Books have addresses and cross-references. They have chapters, sections and pages. All have unique numbers that can be referred to. However, you cannot refer to a thought, an idea or any content. Chapters, Sections and Pages are more like coordinates. A thought might spread over the whole book. You cannot refer to it directly with just one reference. A book is not a web of thought.
  • Wikipedia is not a web of thoughts, because you can only link to articles and sections within them, but not to individual thoughts inside the text. None of the addresses matches with any thought. Wikipedia is not meant to be such a thing. Rather, Wikipedia is an encyclopedia with each article containing information on a topic. Wikipedia is not a thinking tool but a tool for information retrieval.
  • In contrast, referring to an atomic note is unambiguous: when you reference it, you will know what the ‘thought’ is. There should be no room for guesswork. That is what the rule of atomicity means: Make sure that the layer of content and the boundaries between notes match and are well defined.

    Principle #3: Personal 🧑‍🚀

    There is one Zettelkasten per person, and one person per Zettelkasten.

    Thinking is a different process from communicating with another person. You want your Zettelkasten to be a personal thinking tool. If you don’t keep your diary absolutely private, you wouldn’t write some things down, and you’d filter other things, therefore distorting them. Writing for yourself is and should be different from writing for the public.

    Sascha, Zettelkasten Coach

    🧱 The building blocks

    1 . A unique identifier

    This gives your Zettel an unambiguous address.

    2. The body of the Zettel

    This is where you write down what you want to capture: The piece of knowledge.

    3. References

    At the bottom of each Zettel, you either reference the source of the knowledge you capture or leave it blank if you capture your own thoughts.

    Putting the pieces together 🧩

    🔢 "Stages" of Notetaking

    1. Fleeting notes

    These are temporary notes made throughout the day, while thinking or reading.

    Ideally, collect these notes into one "inbox" so they're easier to process later. When it’s time to process them at the end of the day, you will sort through these notes, pick out useful, interesting, or relevant ideas, and either transform them into permanent notes, or discard/archive them.

    You don’t have to make fleeting notes, if you have an idea in mind, simply add directly to your permanent notes.

    When taking fleeting notes from a book, start by writing the title of the book at the top of the page. Then for each idea that meets one or more of the criteria described above, write down the page number the idea was inspired by, and a word or a short phrase that will trigger the full idea in your mind when reviewing the notes at the end of the day (quick processing is critical for these reminders to work).

    Here’s an example:

    Example of fleeting notes in Bear Software.

    2. Literature notes

    These are created for a specific resource, such as a book, article, web page, etc. Notes are taken specifically on the content. These notes are typically filed separately from your permanent notes.

    There are five criteria it would be beneficial for your literature note to meet:

    1. Write it in your own words.
    2. Write it in such away that if you read it 10 years later it would make complete sense by itself.
    3. One idea per note. If you need to define a term for the idea/concept to make sense, create a term definition card and link to it from the concept note.
    4. Include the complete reference for the source you got the idea from.
    5. Include the relevant citation (lastName, year, pp.22).

    Here is an example:

    Example of Literature Note in Obsidian Software

    3. Permanent notes

    Once you have an idea to add to your Zettelkasten, you are ready to create permanent notes (Zettel).

    Linking is a key component of creating your Zettelkasten. Every time you add a new Zettel, look through your previous notes and ask yourself:

  • Is this relevant to my research/thoughts/interests?
  • How can I develop or add to existing ideas/arguments/discussions?
  • Does this new information contradict, correct, support, or add to my thoughts?
  • Can I combine ideas?
  • Source: PKM Zettelkasten, Rebecca Williams

    🕸️ Organizational structure

    Luhmann used "hub" notes. These are Zettels that list many other places to look at for a continuation of a topic. The main benefit of hierarchical structures is the increased potential for knowledge creation.

    A Structure Zettel with fancy table-of-contents markup, and a graph view of the same connections and hierarchy.

    🤩 So why has this system become popular?

    🚀 Google Trends, last 7 years:

    🕹️ Maybe it makes knowledge work more fun?

    The Zettelkasten Method is an amplifier of your endeavors in the realm of knowledge work. It is highly effective, and many people report they have more fun, one even comparing it to the addictive nature of games like World of Warcraft, and have an easier time doing knowledge work overall. But this only comes as a result of putting in a high level of consistent effort.

    Sascha, Zettelkasten Coach

    ❤️ Many users fall in love:

    👀 3 Cool Public Examples

    Andy's notes:

    We've talked about Andy's note below. Still one of the coolest examples out there. He uses the concept of atomic, evergreen notes, and combines it with a fun way to navigate the content as you open up each note like a book. Each note title = hyperlink.


    Cool use of search + displaying results based on what you're looking for. Timestamps and "papertrails" makes each search experience feel like a journey.


    Cool combination of search + tags to find and explore different topics. Feels a bit more serendipitous.