A quick translation provided by the bots that be. "///" indicates paragraph breaks within lists.

Lecture

Münster, 13.1.1968

Technique of the Zettelkasten

I. Statement of the problem

Linear accumulation of information that is meant to remain available.

Memory solves the problem of retrieval independently of the order of input, but it has limited capacity.

With written notes, the same problem reappears. Example: lecture notes.

The solution is quite important and worth careful consideration.

II. External setup

No excessive effort required:

Initially, a portable cardboard box suffices; later, possibly wooden boxes in blocks of four.

Paper slips (octavo size) are entirely sufficient; write on one side only.

Index cards may be used for a keyword index, etc.

III. Order – the central problem

A distinction must be made between topic-specific collections of slips and permanent setups for a course of study or a scholarly life’s work.
Important: each slip must have a fixed location that must never be changed, because retrieval depends on it. ///Removal for use and exact reinsertion. /// This requires numbering the slips. /// There will be long numbers; therefore, alternate between numbers and letters to make recognition faster: 533/15 d 17 a 1 [*].
Filing new slips: attaching them or inserting them in between.
A system of cross-references solves all ordering problems. /// Misplacements must be corrected by cross-references, not by rearranging. /// It is in principle irrelevant, even if sometimes inconvenient, to have related slips under very different numbers. /// What belongs together changes anyway with the question being asked and cannot be schematically decided in advance. /// No straitjacket, but a principle of arbitrariness.
Nevertheless, a certain rough schematic orientation is important at the beginning. /// It makes it easier to find “regions.” /// Where does this come from? /// Reading lists, textbooks. /// Once again: this is not a core problem.

IV. Example: Risk handling in drug adoption

Which keywords: physicians, medications, medicine, firms, advertising?

The obvious choices are too concrete to be usable for other problems.

My interest was: uncertainty, trust.

Cross-references to: risk, error, reduction of complexity.

Another possible framing: medical sociology.

Reaching an appropriate level of abstraction is a slow learning process that builds on what is already present in the zettelkasten.

In this way, conceptual and interest-based focal points consolidate.

V. Content

Excerpts? Only when dealing with formal definitions or concise formulations. /// Do not copy pages verbatim. /// More at the beginning than later; quote precisely
Important: try to formulate things in your own words. /// This makes a strict separation of one’s own and others’ ideas necessary. /// Critical summarizing is at the same time one’s own thinking work, at the same time a learning process, at the same time a honing of one’s own language. /// Lecture notes, notes on conversations, ideas arising on all sorts of occasions can also be worked into the zettelkasten. /// Becoming outdated is unavoidable. ///Proof of learning success.
Furthermore: literature.

a) For books and journal articles that you have had in hand and worked through, a separate section in the zettelkasten is recommended, at the front or back, with slips containing bibliographic information. /// One slip per book. /// Important: limit yourself to information you have personally verified. /// This allows abbreviated citation on the slips.

b) In addition: information on literature not yet read on specific topics should be entered into the zettelkasten itself, in the appropriate place. /// X from notes in the literature you have read, or from reviews, publishers’ catalogs, etc.

VI. Finding the slips

With greater size, this will become problematic.

By and large, two aids suffice for me:

an alphabetical keyword index;
notes on the literature slips, if the problem arises via an author’s name.

VII. In conclusion: from personal experience

Others work differently.

As with all translation, and especially with theoretical works, and especially theoretical works like Luhmann's, translation will be a contested region. There's lots to discuss here. Even the first line has been translated differently across the web as, "A continuous stream of information that should remain available." Very different implications.