The first step in what will eventually become a harmonized world footballing calendar became binding as of January 1 2002.

The new system now calls for all international matches played on certain dates to take precedence over club duties.

Domestic leagues are expected to leave these dates open, as well as releasing players for the requisite training periods proceeding an international. The new policy applies to friendlies as well as competitive matches.

According to FIFA's "Release of players for national association representative matches in accordance with the Coordinated International Match Calendar" regulations, the length of time a player is released for a competitive international is four days, five if the player is overseas, with two days for a friendly.

The specifications also "strongly recommend that all national associations endeavour to arrange international matches on either a Wednesday or Saturday. When possible, we also recommend that national associations try to arrange two international matches in the same calendar week, using the "Wednesday & Saturday" system."

FIFA will add dates for international competitions as they happen, limiting the need for players to choose club versus country for recognized competitions and appropriately scheduled friendlies. If a country isn't competing in a recognized international tournament, those dates become open for friendlies. As with the old system, a club can refuse to send players if a country decides to stage an international friendly outside of the dates specified by the official calendar.