What is the Magnus Number?

It’s the distance of chess victories from any chess player to Magnus Carlsen, the current former world chess champion. The detailed definition can be found on the main page.

How is the Magnus Number computed?

Given a database with all FIDE rated games, one has to construct a graph, where the nodes are the players and the edges correspond to valid victories. The Magnus Number of a player equals the number of steps in the shortest path from the player to Carlsen. Finding the shortest path can be done very efficiently using Dijkstra’s algorithm.

Why does Magnus Carlsen have a Magnus Number of zero?

True, no player can play a FIDE rated game against oneself, so one could argue that the Magnus Number of Carlsen is not well defined.

Is the Magnus Number an official indicator of a chess player’s strength?

No, although there should be some correlation. There are several chess rating systems to measure a chess player’s strength and the official one is the FIDE elo rating.
Nevertheless, a player’s Magnus Number can be regarded as a “badge” or an “achievement”, or just as a “fun fact”.

I don’t have a Magnus Number, how can I obtain one?

By winning a FIDE rated game against an opponent who does. You can check on the main page whether your opponent has a Magnus Number or not.

Can I ever lose my obtained Magnus Number?

No, in contrast to the FIDE rating, a player’s Magnus Number can only improve over time.

How frequently are the Magnus Numbers updated?

All the data on this website is updated every month, when FIDE publishes its new ratings. As Carlsen is not the reigning world chess champion anymore, the Magnus Numbers are now frozen.

Why choosing Magnus Carlsen as a point of reference?

He is the current former world chess champion, he has obtained multiple world championship titles in standard, rapid and blitz time control, he has been number one on the FIDE ranking list for more than a decade and he is the highest FIDE rated player of all time. So why not celebrate his losses for once, as these are a necessity for this website… 😉