Simple Zettelkasten Setup in LaTex

A quick introduction of Zettelkasten can be found on Wikipedia. For a more in-depth discussion, Sönke Ahrens has a nice book on the topic [1].

There are many ways to implement such note-taking approach and most of then use certain general-purpose or specialized note taking software, such as Bear.app, Evernote, Obsidian, Zettlr, The Archive and Roam. But those tools are not essential in my opinion, given that the original system was implemented by Niklas Luhmann with pens, index cards and slip boxes. Luhmann's archive was digitalized and can be found here (in German).

I finished Ahrens's book [1] in the fragmented time when I was waiting my dog to calm down in crate training. I found the idea intriguing and wanted to try it. But I am little reluctant to invest in a new software at the moment. Instead of weighing the pros and cons of various software, I would like to start with something simple and easy to incorporate with my existing workflow. For example, I use Zotero for bibliography management and VSCode for coding and note taking.

You can find many good advice online on how to start with plain text files and a text editor for Zettelkasten. Markdown is a popular choice of file format due to its simplicity and potential to be converted to other formats through software such as pandoc. However, in my field, research papers are mostly typeset in LaTex and I would like to reuse my notes when writing. With sufficient configuration and plugins you may make Markdown work nicely with LaTex. But I decided to skip the hassle and directly note in LaTex.

I quickly set up a simple system for this purpose. A few interesting decisions were made. First, LaTex instead of Markdown is chosen for the file format. The reason has been discussed. Second, the page size is limited to A6 instead of the common A4 or letter size, which better mimics Luhmann's original system (he used DIN A6 index cards, 148x105mm [1, sec. 3.1]). Third, the file naming method follows the convention of the original system. A file name is just a number, bearing no meaning and just as a permanent unique identifier. And related notes will be named similarly. For example, a new note that is related to an existing note 1.tex will be manually named 2.tex or 1a.tex. The next related note will be named 1b.tex or 1a1.tex and so on. Fourth, linking is done manually through LaTex hyperref mechanism, facilitated only by a LaTex command \zl{n} which is just \href{file:n.pdf}{\emph{n}}.

A smaller page size is chosen because the limited space (hopefully) encourages precise and brief writing about things that matters. I also like that fact it mimics the original cards and maybe one day you can print them out, put them in a slip box, then you have a physical Zettelkasten system, which is pretty cool (although may not be useful).

File naming and linking are done manually because, if I understand the idea correctly, they should be deliberate decisions from you when you review the notes, think about how they relate to your writing, develop ideas, arguments and discussions. It's simpler, more portable and software-agnostic (well, it still relies on LaTex of course).

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[1] S. Ahrens, How to take smart notes: One simple technique to boost writing, learning and Thinking–for students, academics and nonfiction book writers. Sönke Ahrens, 2017.

Assumptions

1. Notes are taken in LaTex and reside in one folder.
2. Reviewing and traversing notes are done in PDFs which can be easily compiled from LaTex sources with latexmk, or other compiler with a build script.
3. PDFs need to be in the same folder because href links are linked to PDFs in the current directory. For example, in note 1.pdf a link to note 1a.pdf will be \href{file:1a.pdf}{1a}.
4. A bibliography file named zotero_library.bib resides in the same folder as note LaTex source files.

Of course, some of the assumptions can be relaxed with modifications in the class file. I encourage you to read the cls file and adjust according to your needs.

Installation

Put the jyzk.cls file in your note source directory.

Or put jyzk.cls to your local texmf directory.

On mac:

mkdir -p ~/Library/texmf/tex
cd ~/Library/texmf/tex
git clone git@github.com:jinyangustc/jyzk-cls.git

Commands provided by the class

\zl{n}: creates a new link to the PDF file n.pdf.

\seealso: creates a "See also:" at the bottom of the card in emphasis.

Basic Setup

Folder structure

.
├── 0index.tex
├── 1.tex
├── 1a.tex
├── 2.tex
├── jyzk.cls
├── slipbox
│  ├── 0index.pdf
│  ├── 1.pdf
│  ├── 1a.pdf
│  └── 2.pdf
└── zotero_library.bib

New note

Create a new note with the following template:

\documentclass{jyzk}
\notetitle{Your note title here}
\notedate{Create time}
\begin{document}

Your note goes here.

% \seealso \zl{}
\end{document}

Optional Setup

VSCode snippet

A snippet that allows you type nz (new zettel) to insert the template:

"New Zettel": {
     "prefix": "nz",
     "body": [
         "\\documentclass{jyzk}",
         "\\notetitle{$1}",
         "\\notedate{$CURRENT_YEAR/$CURRENT_MONTH/$CURRENT_DATE $CURRENT_HOUR:$CURRENT_MINUTE:$CURRENT_SECOND}",
         "\\begin{document}",
         "$0",
         "% \\seealso \\zl{}",
         "\\end{document}",
     ]
 }

1. Open the command palette.
2. Call Preference: Configure User Snippets.
3. Select latex.json.
4. Insert the snippet.

Zotero

1. Install Better BibTex plugin.
2. Export your Zotero library in BibTex format and select Keep Updated. Your zotero_library.bib file will be in sync with Zotero. Future changes you make to the Zotero should be automatically made to the bib file.

Example

Notes

Links

File links are highlighted in cyan. Click one will open the corresponding note. The link on the left header, showing the current note's id, will take you to the index card.

Search

Search can be done either in the LaTex source files with your text editor or command line tools such as grep or rg. Or in PDF files with system search tools. For example, on macOS: