Last modified: Monday, August 25, 2008 3:08 AM EDT Vijay Singh holds The Barclays cup after winning The Barclays tournament, the first of four stops in the FedEx Cup playoffs, on the second playoff hole. C7 Delivering a lesson on the FedEx Cup BY MIKE KIRBY SUN CHRONICLE STAFF NORTON - Sure, you know about the Masters, and the U.S. Open and the British Open and the PGA Championship. And you probably know about the Ryder Cup. But what exactly is this FedEx Cup and why should you care? Here is FedEx Cup 101, an explanation of the PGA Tour's second annual attempt to crown the top golfer of the year and what to watch for as the world's best golfers come to the TPC Boston in Norton later this week. What it is: The FedEx Cup is the PGA Tour's version of the playoffs. There are four events: The Barclays (this weekend), the Deutsche Bank Championship (next weekend at the TPC Boston in Norton), the BMW Championship (Sept. 4-7) and The Tour Championship (Sept. 25-28). The Not everyone gets in: More than 250 PGA Tour pros have played a PGA Tour event. Only the top 144 in FedExCup point standings earn the right for a shot at the FedExCup trophy. That's why they're called the playoffs. Not everyone stays in: Each week, the fields will narrow, from 144 players to the final 30-player field at The Tour Championship. After The Barclays, the field narrows to 120 players: 24 get eliminated. After the Deutsche Bank Championship, 50 will go home to create a 70-player field. And another 40 end their season after the BMW Championship, forming the final 30-player field. It's about who performs best in all four events: The winner of the FedExCup will be the player who has accumulated the most points throughout the playoffs, not necessarily the winner of The Tour Championship. Each week, the every player needs to finish as high as possible - not simply to stay in the field for the next event, but to have a chance to win the FedExCup. Cuts hurt but eliminations are final: Cuts are those Friday annoyances that keep players out of the weekend play and purse. But eliminations will end a player's season. This week's Barclays and next week's Deutsche Bank Championship in Norton will still feature cuts in order to get the weekend field down to 70. But they'll also see players eliminated for good. All bets are off for the BMW championship. All 70 players will start and complete the tournament, but over half will be eliminated before The Tour Championship. Watch the Bubble: As each playoff tournaments progresses, keep your eye on the bubble - the 10 players who have a chance of advancing or getting cut and going home at the end of the weekend. You can count on there being as much action here as there will be atop the leaderboard. Watch the leaderboard AND the points: While the tournament leaderboard determines how many points a player gets each weekend, it doesn't determine where he ends up in the standings. That's a combination of how he got seeded in the initial 144-player field, how he performs each week, and how the others rise or fall around him. 30 is a magic number: Staying true to tradition, the final championship-contending field will consist of the top 30 players - those who played well throughout the season plus those who held their ground or overcame the odds during the playoffs. MIKE KIRBY can be reached at 508-236-0344 or at mkirby@thesunchronicle.com.