Quick Facts

  • Zettelkasten Method is a method of note-taking and organization. It is German for “slip box”.
  • Popularized by Niklas Luhmann1
  • Great for building a second brain
  • Can help find connections between notes
  • Useful for thinking more broadly by not confining your notes to a subject

So basically, the Zettelkasten Method relies on interconnectivity of information, and atomicity of concepts. You make notes that work independently. If you feel a connection, you note it down.

Luhmann’s Zettelkasten - The Method in His Words

Luhmann used a physical box of cards. Made 90,000+ handwritten notes. Some of Luhmann’s comments on the method (emboldening by me) -

“Underlying the filing technique is the experience that without writing, there is no thinking.

“I always read with an eye towards possible connections in the slip-box.” 2

“I, of course, do not think everything by myself. It happens mainly within the slip-box.”

(The zettelkasten is a) “combination of disorder and order, of clustering and unpredictable combinations emerging from ad hoc selection.”

”Probably the best method is to take notes – not excerpts, but condensed reformulated accounts of a text. Rewriting what was already written almost automatically trains one to shift the attention towards frames, patterns and categories in the observations, or the conditions/assumptions, which enable certain, but not other descriptions.”*

— Niklas Luhmann

Principles of Zettelkasten

  1. Note taking - Take notes. Not excerpts, but how you understand it. In your own words.
  2. Atomicity - He realised that one idea, one note was only as valuable as its context, which was not necessarily the context it was taken from. So, one idea per note.
  3. Autonomy - Notes should make sense by themselves too.
  4. Connect Notes - Try to link all notes. “A note that is not connected to the network will be lost, will be forgotten by the Zettelkasten”
  5. Number your notes - use any numbering system and stick to it. It’s just a way to identify the cards for linking. The numbers do not mean anything. The point of the method is not having to worry where a note goes.

The core of the technique lies in a few simple principles:

  • Write liberally about what you think and read. Write in detail so you can quickly re-internalize ideas after you forget them.
  • Wherever you can, separate notes into small and distinct ideas.
  • When you notice connections between ideas, encode them by writing references from one note to another.
  • When you want to think or write, read your notes and follow the references between them.
  • Update as you go. Find something new to add? Add it. Don’t agree with something you had written once? Don’t trash the old note! Make a connection to the new one and explain why you changed your mind.


    • Niklas Luhmann was a sociologist and a prolific writer having published as many as 70 books and nearly 400 scholarly articles. His main work was in Systems Theory. Luhmann himself described his theory as “labyrinthine” or “non-linear” and claimed he was deliberately keeping his prose enigmatic to prevent it from being understood “too quickly”, which would only produce simplistic misunderstandings!
    • Personal note - This is what helped me the most and why I find this method pretty much life-changing. It has changed the way I process things, the way I learn things. This way, I’ve been more mindful of what I’m reading, what is important. As a result, I’ve been able to retain more.