The knowledge graph, for beginners

“Knowledge graph” sounds technical. The idea is simple enough to fit on a subway map.

A subway map

Each station is a note. Each line between two stations is a link. In the jargon, stations are nodes and lines are edges, but you don’t need the words to use it. A note with no link is a station no line serves: it exists, but nobody ever goes there.

A link has a meaning

A folder answers the question “where is this document stored?”. A graph answers “what is it connected to?”. A meeting note can be filed in only one folder, but it can be linked to the client, the project, the method discussed and the colleague present. In a folder, it lives in one place. In a graph, it is reachable from four.

The link carries the meaning: “Martin works at Acme”, “this article contradicts that one”. Two notes side by side in a folder say nothing. Two linked notes say something.

In Obsidian, with nothing to install

• Typing [[Note name]] in a note creates a line. If the note does not exist yet, Obsidian shows the link in a different colour: it is a station to be built.
• The graph view (icon in the left sidebar) draws the map of all your notes.
• The backlinks panel shows, for the note you are reading, every note that points to it.

What it changes for the AI

Without links, to answer a question, Claude would have to read every note. With links, it starts from the right station and follows the lines. Less reading means fewer tokens, which is the subject of module 5. Your rules file asks Claude to add links in both directions every time it files a document: that is how the graph builds itself.

Reading your graph

What you see	What it means	What to do
A big dot with many lines	A hub: one of your central topics	Check its note is up to date: many others depend on it
An isolated dot	An orphan: nothing points to it	Link it, or delete it if it is useless
A dot between two clusters	A bridge: it connects two worlds	Keep it carefully: these are the notes that produce ideas
Separate clusters	Areas of your life that never meet	Sometimes normal, sometimes a missing link to create

The links/ folder exists for bridges. When a document connects two topics that were not connected, Claude creates a note there. On a well-maintained brain, these are often the most useful notes, because they say something no single source says.