There are 28 matches played between European and American players over the course of the Ryder Cup weekend, with each match being worth one point. The winning side is the team that accumulates the most team points, with a draw seeing the reigning champ retain the trophy. This means that the defending champs need 14 points to win, while the challengers require 14 1/2.
The Ryder Cup team scoring system seeks to make an easily quantifiable measurement of which team has played better over the course of the Ryder Cup weekend. On a grander scale, the Ryder Cup itself is a means of seeing where the premier golfers in the world call home, and also offers the opportunity for some players to face members of the other golf tour, who they may normally only face in major tournaments.
The Match Types
There are three different types of matches played over the course of the weekend. There are two days that see four rounds of foursomes and four rounds of four ball each. In foursomes, two players from each team play together, alternating shots on the same ball. In four ball, each player plays their own ball, with a player needing to beat both players on the opposing team to win the hole. The final day sees the final twelve matches, with each team sending all players out in one-on-one match play.
All matches use match play scoring, meaning the winner is whichever side wins more holes, regardless of how much each hole is won by. If over the course of one match the European side won two holes by one stroke each, the American side won one hole by three strokes, and they tied the remaining holes, the European side would win despite using more strokes.
The Ryder Cup scoring system has led to some dramatic finishes. The most iconic of these was the United States' rally in the 1999 Ryder Cup. The Europeans entered the final day with a 10-6 lead, and seemed sure to win. The Americans staged a massive comeback, winning 8 ½ points in the heads-up matches, culminating in Justin Leonard sinking a long putt to seal the comeback--setting off a raucous, controversial celebration on the green.