Zettelkasten Method | Simply Explained

Shu Omi
4 min readJun 11, 2020


Zettelkasten method is one of the most effective knowledge management methods. But it’s not known by many people.

The word Zettlelkasten means “box of cards” in German. This method was developed by Niklas Luhmann, a German sociologist.

He may not be as famous as folks such as Stephen Hawking and Albert Einstein, but what made him stand out from the crowd was his writing efficiency. In 30 years, he published 58 books and hundreds of articles.

How did he manage to write so much?

It’s thanks to his unique knowledge management system — Zettelkasten. Zettelkasten allowed him to:

  1. build a huge web of knowledge;
  2. retrieve the right memory when needed;
  3. find meaningful connections among topics, and
  4. develop his ideas, arguments and discussions efficiently.

The process of Zettelkasten is simple. All you need is small boxes, index cards and a pen.

Luhmann had two boxes: one for bibliographical notes with the references details and brief notes about the content of the literature, and the main box where he collected and created new ideas and insights.

The first step of Luhmann’s Zettlekasten is taking Literature notes.

When you are reading a book or an article, always have a pen and index cards with you. And when you find the information you don’t want to forget or think you might use in your writing or thinking, write it down in an index card, instead of highlighting or underlining.

But, you have to be careful that:

  1. it has to be brief to make it easy to review later, and
  2. you have to write it in your own words. This means no copy and pasting. Writing in your own words may take a while, but it forces you to really understand what you’re reading.

The second step is taking bibliographical notes whenever you finish reading something.

Luhmann wrote down the reference information on one side of a small index card and a brief note about the content on the other side. Then he kept the cards in the bibliographical box with the Literature notes.



Shu Omi

I’m a former data scientist and now a full-time creator. I share what I learned about personal knowledge management and building an online audience