The structure of zettelkasten is actually quite simple. But this Simplicity allows complexity to emerge.
niklas luhmann’s original structure had three main elements:
- a bibliographical slip-box that contained references and brief notes about the contents of these references,
- the main slip-box that contains his own ideas (mostly responses to what he read), and
- an index that contains one or two notes that serve as entry points to a large topic.
For the notes, Luhmann used index cards. For the slip-boxes, he used wooden boxes.
How Luhmann used the bibliographic slip-box
Luhmann took one index card. Whenever he read something, he wrote its bibliographic information on one side and brief careful notes of its contents in the other. He wrote these notes as if he was writing a paper. He used full sentences and explicit references to other literature if necessary.
How Luhmann used the main slip-box
After doing the previous steps, Luhmann looked at the brief notes he wrote about the reference he read (he did not make any highlights when reading). He then thought about the relevance of these notes to his own thinking and writing. He wrote new notes capturing his own thoughts in new index cards: one idea in one card. He kept these brief restricting himself in one side of the paper. When he needed to extend a thought, he writes a new note. If notes follow one another, they form a chain of notes. He made connections between existing notes and new notes.
When the time comes for Luhmann to sort notes into a single topic, he creates a new note that sorts relevant links. He does not organize his notes by topic. Instead, he organizes them by giving each note a fixed number. For example, if a new note follows an existing note numbered 22, its number becomes 23. If 23 already exists, its number becomes 22a. If more notes follows 22a, he alternated between numbers, letters, commas, and slashes like 21/3d7a7 follows 21/3d7a6.
This process was what inspired Ahren’s Zettelkasten Manual and andy matuschak’s Evergreen note-taking system.
References
Ahrens, S. (2017). How to Take Smart Notes: One Simple Technique to Boost Writing, Learning and Thinking – for Students, Academics and Nonfiction Book Writers.