After working with historical game collections to write Another Fictitious Match and 1946 Alekhine - Botvinnik, I got the urge to look at the opening repertoire of a modern player. GM Carlsen seemed like a good choice. Although I've played through many of his games, I've never developed an appreciation for the opening systems he prefers. Looking at his games in more depth might teach me a thing or two.
I found a good collection of 1395 of his games at Chess Grandmaster Magnus Carlsen Fansite - Games, loaded it into a database, and discovered that it stopped in January 2011, with the 73rd Tata Steel GMA group at Wijk aan Zee. To bring the games up to date, I first looked at Carlsen, Magnus PGN Chess Games FIDE on ratings.fide.com, and downloaded files for the events I was missing.
The FIDE files turned out to be problematic. They were not all in the same text format, some were missing mandatory PGN header tags, and there was junk prepended to one file. On top of that, the files had games for players other than Carlsen and some files were incomplete for him. Instead of struggling with those files, I decided my time would be better spent extracting the games from TWIC downloads. TWIC files are big and somewhat cumbersome, but they are always consistent and accurate.
In Carlsen's TWIC Debut, I once traced the Norwegian's first mention in TWIC to April 2001. I didn't need to go back this far, so I only examined TWIC files back to mid-2010. This gave me 167 recent Carlsen games. The total of 1562 game compared favorably with the 1427 games currently in the Magnus Carlsen collection on Chessgames.com. Why the difference? I'll leave that question to a more diligent researcher. As for my new collection, I'll take a closer look at GM Carlsen's repertoire in another post.