Beer, this is how the NHL explains it:

NHL SCHEDULE FEATURES
RIVALRY-BASED FORMAT

NEW YORK (July 22, 2005) - The National Hockey League is returning with an exciting new regular-season schedule format that emphasizes division rivalries.

Format

    * Each club will play eight games against each of its four division rivals (32 total).

    * Each club will play four games against each of the 10 non-division clubs in its conference (40 total).

    * Each club will play 10 inter-conference games, hosting one game each against all five clubs from a designated division and traveling for one game each against all five clubs from a different division. For the 2005-06 season, Northeast Division clubs will host the Pacific Division and visit the Northwest; Atlantic Division clubs will host the Northwest and visit the Central; and Southeast Division clubs will host the Central and visit the Pacific. Division vs. division assignments will rotate annually.

Features

    * The new schedule strengthens division rivalries; division rivals played each other six times under the previous schedule.

    * The new schedule maintains integrity of the conference-based playoff format; each club continues to play 40 games against non-division, intra-conference opponents.

    * The new schedule allows for continued exposure of teams and star players from the other conference.

    * The new schedule allows for more compelling television matchups, thanks to the combination of stronger division rivalries with continued intra- and inter-conference play.