Chess Archives is no longer published but in its day it provided the cutting edge of chess opening theory. It was published monthly by a team of Dutch chess opening analysts, headed by former World Champion Dr. Max Euwe. It was intended to be held in a loose-leaf ring binder. Every month new sheets would arrive. The reader was to insert the new sheets into spaces in the binder according to a coding system. In some cases the old sheets were to be removed and thrown away. Chess Archives was the first publication to introduce a numerical classification of openings. Nowadays, ECO provides the world recognized standard. Chess Archives introduced the system where you had to look at the list and get the Opening Key. For example, the Dragon Sicilian is 14a. If a new opening trick or trap were discovered, one could be sure it would appear soon in Chess Archives. Readers of established books like Modern Chess Openings could have an unpleasant surprise when a line the were playing had been refuted by new discoveries. That was unlikely to happen to any reader of Chess Archives because the new issues would always contain the latest stuff. Bobby Fischer was known to read and devour Chess Archives because he often played new lines that had just appeared in Chess Archives. In one famous game where his opponent had followed Chess Archives, Fischer had found a bust and refuted it in spectacular fashion.