How to Take Smart Notes by Sönke Ahrens

Big thanks to Lionel for gifting me this ebook. A deep dive into Sönke Ahrens' systematization of the Zettelkasten method - from fleeting notes to permanent insights, and how I integrated it into my daily workflow.

The Gift That Changed How I Think

big thanks to my life teacher Lionel for this ebook. if you’ve read my bash notebook or my Google SRE interview story, you’d know Lionel was one of my mentors at Pixium Digital, where i started my career as an intern. he’s been gifting me books since day one - always pushing me to learn, grow, and think differently.

last year, sept 18, we had a solid catchup. talked about work, school, life - the usual. i shared how i do my “project management” (aka organized chaos in Notion), and he introduced me to this methodology + his Bear → Notion workflow. then he sent me this ebook: How to Take Smart Notes by Sönke Ahrens.

i’m someone who loves learning. i go deep on anything that sparks my curiosity. but here’s the problem: i was learning a ton… and forgetting most of it. highlighting, scribbling notes, telling myself “i’ll organize this later” - classic trap.

this book changed that. completely.


TL;DR

Core concept: Writing IS thinking, not the outcome of thinking.

The method: Zettelkasten (slip-box system) developed by German sociologist Niklas Luhmann.

The workflow: 3 note types → 6-step process → networked knowledge base.

The result: Notes that compound. Ideas that connect. Writing that flows naturally.


The Problem: Why Traditional Note-Taking Fails

let’s be honest. most of us take notes like this:

  1. Highlight everything (because it all seems important in the moment)
  2. Never revisit (out of sight, out of mind)
  3. No connections (each note lives in isolation)
  4. “I’ll organize later” (narrator: they never organized it)

i’ve been there. thousands of highlights across Notion, Apple Notes, markdown files on GitHub. some of it brilliant. most of it forgotten.

the traditional approach treats notes as storage - a place to dump information and hope you remember where you put it.

the Zettelkasten method treats notes as thinking - a place to develop ideas and let them grow.


The Zettelkasten Method

What Is It?

Zettelkasten = German for “slip-box”

developed by Niklas Luhmann (1927-1998), a German sociologist who published 58 books and hundreds of articles using this system. his secret? a physical box of index cards, each containing one idea, all linked together like a web.

Sönke Ahrens systematized Luhmann’s method in 2017, making it practical for modern knowledge workers.

The key insight: a note is only as valuable as its context - its network of associations, relationships, and connections to other information.

The 3 Note Types

TypeLifespanPurposeExample
Fleeting Notes1-2 daysQuick capture during reading/thinking“Check out Zettelkasten method”, “Why does for…else confuse me?”
Literature NotesPermanentConcise source summary in own wordsSession notes from TCX1002 Tutorial 3 with context
Permanent NotesForeverAtomic insights - one clear idea per notefor-else-pattern.md, k-length-optimization.md

Critical rule: fleeting notes MUST be processed within 1-2 days. after that, you lose the context and they become useless.


The 6-Step Workflow

here’s how it works in practice:

1. Read / Observe

During class, work, conversations, books - consume information actively, not passively.

My example: TCX1002 Tutorial 3 - working through Python pattern matching problems.

2. Create Fleeting Notes

Quick dump of thoughts as they happen. raw, unpolished, just capture.

My example: _fleeting/2026-01-29.md - “for…else keeps tripping me up”, “dict overwrites duplicate keys - gotcha!”

3. Create Literature Notes

Within 1-2 days, review fleeting notes and sources. write extremely concise summaries in your own words.

My example: Session notes in 000_mods/sessions/2026-01-29/session-notes.md - full context of the tutorial session.

4. Transform into Permanent Notes

The magic step. review your fleeting and literature notes. ask: “What’s worth keeping forever?”

extract atomic insights:

  • One concept per note
  • Full sentences (write for others, not just yourself)
  • Self-contained (should make sense without original source)
  • Link to related notes during creation (not after!)

My example: Created 3 permanent notes:

  • for-else-pattern.md - How Python’s for…else works
  • k-length-optimization.md - Pattern matching optimization technique
  • dict-overwrites-duplicate-keys.md - Python dict overwrite behavior

5. Store in Zettelkasten (Networked System)

File the permanent note in your system. link it to related notes. let it connect naturally.

My setup:

  • 000_mods/notes/ - all permanent notes
  • Cross-linked with [[note-name]] syntax
  • Organized by context, not topic

6. Use for Writing / Output

When you need to write something (blog post, essay, report), you don’t start from scratch. you already have notes!

My workflow: When 3+ permanent notes cluster around a theme → blog post emerges naturally.

This blog post? Direct result of the Smart Notes system i built using this method.


The 10 Principles (Deep Dive)

these principles (via Forte Labs) are the why behind the how:

1. Writing is not the outcome of thinking; it is the medium in which thinking takes place

you don’t think first, then write. you think by writing. writing forces clarity. if you can’t write it clearly, you don’t understand it yet.

how i apply it: i process fleeting notes by writing them as permanent notes. the act of writing reveals gaps in my understanding.

2. Do your work as if writing is the only thing that matters

consume information with the goal of potential publication in mind. doesn’t mean you’ll publish everything - but the mindset changes how you engage.

how i apply it: when i read/learn something, i ask: “could i explain this to someone else?” if yes → permanent note.

3. Nobody ever starts from scratch

all creative work builds on existing knowledge. the myth of the “blank page” is just that - a myth.

how i apply it: my blog posts now emerge from note clusters. no more staring at empty documents.

4. Our tools and techniques are only as valuable as the workflow

fancy tools mean nothing without a system. obsidian, notion, roam - doesn’t matter if you don’t have a workflow.

how i apply it: i use simple markdown files + git. the workflow (3 note types → daily processing) matters more than the tool.

5. Standardization enables creativity

using a consistent format for notes frees your mind to think flexibly. you’re not deciding “how should i format this?” - you’re just writing.

how i apply it: all permanent notes follow the same structure: concept → explanation → example → related notes → source.

6. Our work only gets better when exposed to high-quality feedback

notes in isolation don’t improve. sharing, discussing, testing ideas - that’s where growth happens.

how i apply it: publishing blog posts from notes = public feedback. teaching others = ultimate test of understanding.

7. Work on multiple, simultaneous projects

having diverse interests increases the chances of unexpected insights. connections emerge between unrelated fields.

how i apply it: i’m juggling TCX1002 (programming), TCX2101 (calculus), TCX1004 (math logic). the cross-pollination is wild.

8. Organize your notes by context, not by topic

don’t file notes by subject. file them by where and how they might be useful in the future.

how i apply it: instead of folders like “Python” or “Math”, i link notes by what they help me do. for-else-pattern.md links to break-vs-reset.md because they’re related traps in control flow.

9. Always follow the most interesting path

let curiosity guide you. rigid plans kill motivation. follow what excites you, and the work becomes effortless.

how i apply it: if a concept sparks curiosity during processing → i go deeper. that’s how k-length-optimization.md was born - wasn’t in the tutorial, but i optimized the solution anyway.

10. Save contradictory ideas

don’t just collect information that confirms what you already believe. preserve conflicting perspectives.

how i apply it: when i find different approaches to the same problem, i save both. develops nuanced thinking.


How I Implemented This

Before vs After

BeforeAfter (Smart Notes)
Session notes → forgottenSession notes → Atomic notes → Blog posts
Thousands of disorganized highlightsNetworked thinking system
“I’ll organize later” (never did)10-15 min daily processing ritual
Notes in silosNotes that connect and compound
Writing from scratchWriting from existing notes

My Current Setup

The Four Layers:

LayerWhatLifespanWhere
FleetingQuick captures during work/class1-2 days (delete after processing)000_mods/_fleeting/YYYY-MM-DD.md
LiteratureSession logs with refsPermanent000_mods/sessions/YYYY-MM-DD/
PermanentAtomic concept notesForever000_mods/notes/
PublishedPolished synthesisForeverBlog, docs

Daily Habit (10-15 min):

every evening:

  1. Open today’s _fleeting/ notes + recent session notes
  2. Ask: “What’s worth keeping forever?”
  3. Create 1-3 permanent notes:
    • One concept per note
    • Full sentences (write for others)
    • Search existing notes → link related ones
    • Add source (module, date)
  4. Delete fleeting notes

Why delete fleeting notes? forces you to process them. if you keep them “just in case”, you’ll never actually transform them into permanent notes.

The Result

Before this system:

  • learned a ton → remembered fragments
  • ideas stayed isolated
  • writing felt like pulling teeth

after this system:

  • learned a ton → captured insights
  • ideas connect naturally
  • writing flows from existing notes

this blog post? not written from scratch. assembled from permanent notes + fleeting thoughts + the research i did earlier. that’s the power of the system.


Key Takeaways

1. Writing forces clarity if you can’t write it clearly, you don’t understand it. writing IS thinking.

2. Atomic notes > long documents one idea per note. easier to link, easier to reuse, easier to understand.

3. Link during creation, not after when you create a permanent note, immediately link it to related notes. waiting = forgetting.

4. Let blog posts emerge naturally when 3+ notes cluster around a theme, a blog post wants to be written. don’t force it.

5. Daily processing ritual prevents backlog 10-15 min every evening. process fleeting notes before they lose context.

6. Delete fleeting notes sounds scary. but it forces you to actually process them. if it’s important, it becomes a permanent note.

7. Organize by context, not topic ask: “when will i need this?” not “what category does this fit?”

8. Start simple you don’t need fancy tools. markdown files + links = enough.


Common Pitfalls (and How to Avoid Them)

PitfallWhy It HappensHow to Avoid
Not processing fleeting notes within 1-2 daysBusy schedule, “i’ll do it later”Set a daily 10-15 min ritual. non-negotiable.
Copying verbatim instead of using own wordsEasier, fasterForce yourself to explain it. if you can’t, you don’t understand it.
Failing to link notesForget to do it during creationMake linking part of the creation process. not optional.
Mixing project drafts with permanent knowledgeConvenienceKeep them separate. permanent notes = timeless. project notes = temporary.
Collecting without processingFeels productiveCollection ≠ learning. processing = learning.
Over-organizingPerfectionismSimple folders. let links do the organizing.

Why This Matters

1Without system: Learn → Forget → Relearn → Forget
2With system:    Learn → Capture → Connect → Build

this isn’t just about note-taking. it’s about thinking better.

the zettelkasten method:

  • forces you to understand (writing in own words)
  • helps you connect (linking related ideas)
  • enables you to create (assembling existing notes)

your notes become a second brain - a networked thinking partner that grows smarter over time.

and the best part? it compounds. every note you add makes the system more valuable. the connections multiply. the insights emerge.


Credits & Thanks

Sönke Ahrens - for systematizing Niklas Luhmann’s method and making it accessible. this book is a masterclass in knowledge work.

Lionel - for gifting me this ebook, for believing in me since my intern days, and for always pushing me to learn and grow. thank you for sharing your Bear → Notion workflow during our sept 18 catchup. this book changed how i think.

Niklas Luhmann - for developing the zettelkasten method and proving it works (58 books!).

You - for reading this far. if you’re a student, knowledge worker, or anyone who learns for a living, i highly recommend this book. it’s not about taking more notes. it’s about thinking better.


WIP: Future Explorations

things i want to dive deeper into (future blog posts?):

  • Tools comparison: Obsidian vs Roam vs Notion vs plain markdown
  • Advanced linking strategies: how to create “hub notes” that connect themes
  • Research-heavy topics: how to handle academic papers with this system
  • Visual thinking: diagrams, mind maps, concept maps in zettelkasten
  • Team knowledge bases: can this work for teams, or is it inherently personal?

if any of these interest you, let me know! might write about them next.


all concepts excerpted from How to Take Smart Notes: One Simple Technique to Boost Writing, Learning and Thinking by Sönke Ahrens (2017). this material may be protected by copyright.

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