Magnus Carlsen's Performance in Nanjing

By Jeff Sonas

Many people have already sent me email, asking where I think Magnus Carlsen's recent performance at Nanjing fits, among the all-time great performances. My calculations indicate that it is the best tournament performance since Garry Kasparov at Linares 1999, and is one of the 20 best tournament performances in chess history. It is certainly the best performance of any kind by a teenager.

My Chessmetrics website includes historical ratings for players from 1843 through January 2005, and this allows us to look at tournament performances across history in an attempt to measure the "greatest" performances ever. There are a couple of significant challenges with this. One is that the raw performance rating, typically used to measure performance, does not reward players who achieve strong results over a longer event, vs. someone achieving the same percentage score across a short event. Thus I have developed a formula that is "more convinced" by more games.  It indicates my best estimate of a player's strength, if we had no evidence other than that one event to guide us.

Another challenge is how to compare ratings across time, a very complicated and controversial topic that includes the inflation debate. I don't want to get into all that right now; hopefully it is sufficient to say that all Chessmetrics ratings and performance ratings are expressed in 2005 terms, and so if you want to compare performances from 2009 against what are currently shown on my website, and you want to use 2009 FIDE ratings, then you need to first subtract 29 points from everyone's FIDE ratings. So instead of Carlsen having scored 80% against 2762-rated opposition, he is treated as having faced 2733-rated opposition, due to FIDE rating inflation since 2005.

Anyway, there are lots of little details to talk about, but probably you just want to see the lists!  I have decided to exclude matches from the first two lists below, and to only consider tournaments. Here is a list of the best tournament performances of the past five years; you can see that Carlsen's performance tops the charts ["opp." is the average rating of the opponents in the event]:

Best Tournament Performances since January 2005

In fact it certainly appears to be one of the 20 best tournament performances of all time, and probably the greatest performance since Garry Kasparov at Linares 1999.  Here is my list, updated to the present, of the 25 best tournament performances of all time:

Best Tournament Performances of All Time

By the way, people often ask about Bobby Fischer's 100% score at the U.S. Championships in 1963.  His performance is penalized due to the strength of his opponents; my formula would put him in a tie for 32nd all-time along with Veselin Topalov at San Luis 2005.

Finally, it is notable that Magnus Carlsen is still only eighteen years old.  There is no doubt in my mind that this is the greatest performance ever by a teenager.  Here is a list of the 20 best performances of all time by teenagers (including all kinds of events):

Best Performances by Teenagers

Links Official tournament site All games in PGN All ChessBase reports on Nanjing 2009 The games are being broadcast live on the official web site and on the chess server Playchess.com. If you are not a member you can download the free PGN reader ChessBase Light, which gives you immediate access. You can also use the program to read, replay and analyse PGN games. New and enhanced: CB Light 2009!