Building a knowledge graph in Notion

6 November 2026

A knowledge graph and a zettelkasten want the same thing. Not a single note, but the ideas that come from the shape notes make once they are linked. The zettelkasten began as Niklas Luhmann's paper slips, each tied to others by an index number, and that pile of cards produced roughly 50 books and 550 articles. The point was never the card. It was the links between cards.

Notion already has the pieces to copy this. Mentions point one note at another, relation properties make an explicit link, and subpages branch out. All three are stock Notion features doing exactly what Luhmann's index numbers did.

One thing is missing: a desk to spread the slips out on. Luhmann physically flipped through the box and felt by hand which cards clustered and which sat alone. Notion hands you a table or a board instead: one database at a time, as rows. Once the links run into the hundreds, there is nowhere to see the shape of the whole.

So people who run a Notion zettelkasten for a while tend to say the same thing. Mentions and relations keep piling up, but seeing what has clustered and what is sitting empty means opening notes one at a time and holding the picture in your head.

Notion-mind draws that structure directly. It reads mentions, relations and subpages, and lays notes and databases out as points with connections as lines. Hover one and only its neighbours stay visible; filter to see only the notes nothing links to. It is Luhmann's box, flipped through on screen instead of by hand.

See what shape your own notes are clustering into.