A look at the rules and scoring for some Olympic sports:
ARCHERY
The men's and women's individual tournaments are single-elimination, with 64 archers competing in each event. The target has 10 evenly spaced concentric rings, each with a score between one and 10. Two center yellow ring brings the highest scores - nine and 10. During individual elimination rounds, each archer shoots 12 arrows and the high scorer moves on.
There also are team tournaments. Each team has three archers who shoot eight arrows apiece. The highest total score wins the match.
The multicolored target is 48 inches in diameter but to an Olympic archer standing 86.4 yards away the target looks about the size of a thumbtack held at arm's length.
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ATHLETICS
In running events, the mission is simple: Whoever crosses the finish line first wins. Under a new rule put in place for this Olympic cycle, there are no ''free'' false starts, meaning anyone who jumps from the blocks early is disqualified from the race on their first violation. That's how Usain Bolt was knocked out of the 100 meters at the world championships last year, paving the way for another Jamaican, Yohan Blake, to win. In the 100 and 200, a time is eligible to be a record only if the tailwind doesn't exceed 2 meters per second.
Field events are also fairly clear-cut: Whoever throws the furthest or jumps the highest or longest gets the win. In most field events, athletes get three chances in qualifying, then three more in finals, to post their best mark. In most events, a mark recorded in qualifying can count as a winning score if nobody surpasses it in the final rounds.
Things get a bit messier in the decathlon (10 events for men) and heptathlon (eight events for women). In these ''multi-events,'' every time or distance corresponds to a point value that is added to an athlete's overall score after every event. The decathlon traditionally ends with the grueling 1,500-meter run, but it's not unusual for somebody who finishes that race in fourth or fifth place to win the overall gold because he or she has amassed such a big lead in the previous events.
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BADMINTON
Badminton players use a racket to hit a shuttlecock over a net that is 5-foot-1 high at the post and sags 1 inch in the middle. The shuttlecock has a leather-covered cork topped by 16 feathers from the same goose, preferably the left wing which is considered the strongest. Shuttles fly at speeds of up to 155 mph.
A match is the best of three games. A game is the first to 21 by a margin of at least two.
Medals are available in men's and women's singles and doubles, and mixed doubles. The 16 group winners in the singles and eight best doubles pairs advance to the knockout stages.
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BEACH VOLLEYBALL
Matches are played under the rally scoring system, in which a point is awarded on each serve (as opposed to sideout scoring, in which only the serving team can score a point). Each match is best of three sets, with the first two sets played to 21 points and the third played to 15. The minimum advantage in a completed set is two points.
Six pools consisting of four teams apiece play round-robin, with the top two in each pool advancing along with the top four third-place teams to a 16-team, single-elimination round.
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BOXING
The London Games will be the last major international amateur boxing competition to use computerized scoring, the much-derided system created 20 years ago to replace the incompetent judging that memorably cost Roy Jones Jr. a gold medal in Seoul.
A panel of ringside judges pushes a button every time the judge perceives a punch landing on a fighter's opponent, and a computer evaluates and tabulates the scores, revealing the results on a round-by-round basis. Although it's difficult to corrupt, the system also is notoriously subjective. It places emphasis on reflex times and punch volume over style and power. The computer scores also allow losing fighters to complain endlessly about their unfair treatment, a dismayingly common theme at the Beijing Games.
The only other major difference in amateur boxing is the headgear - also headed for the scrap heap after London. The men fight three 3-minute rounds, while the competitors in the first women's boxing tournament will fight four 2-minute rounds.
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CANOEING
This Olympic sport can be divided into two different segments: sprint and slalom.
In sprint, canoes or kayaks race in eight lanes along a flat-water course, and the first boat to the line wins. Races are held at three distances - 200 meters, 500 meters and 1,000 meters - and either solo, pairs or fours.
In slalom, canoeists or kayakers are timed as they paddle down a 250-meter course dropping 5 1/2 meters from start to finish, along which competitors must pass through up to 25 gates. Red gates must be negotiated upstream and green gates downstream. Touching a gate adds a two-second time penalty to the run and missing a gate results in a 50-second penalty. The time taken to run the course in seconds is added to any penalties to give the overall score.
Athletes race either solo or in pairs. There are three categories - canoe single (C-1), canoe double (C-2) and kayak single (K-1). Women only compete in the kayak event.
Athletes kneel and use a single-bladed paddle to propel themselves in canoes. In a kayak, athletes sit and can use both ends of the paddle.
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CYCLING
Road cycling, BMX and mountain biking are among the events in which the entire field or a group of finalists are on the course at the same time, and the first rider to cross the finish line wins. Other events, such as the road time trial, are races against the clock, with cyclists on the course trying to post the best time.
The only event that is a departure from either of those scoring methods is the omnium, which is a new addition to the track cycling slate for the London Games. Riders compete in a series of six events - the flying lap, points race, elimination race, individual pursuit, scratch race and the time trial - and receive points in reverse order based on their finish. The rider with the fewest points after all the events is the winner.
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DIVING
Even with precise performance criteria for each dive, judging is mostly subjective. The personal preference of each judge influences how they rate a dive. Style is what sets a diver apart even as one or more of them attempts the same dive.
Judges evaluate five parts of a dive to determine an overall score: approach, takeoff, elevation, execution and entry.
Entry is important because it's the last thing a judge sees. Judges favor a graceful, vertical entry along with a minimal amount of splash.
Each judge scores a dive between zero and 10 points, which includes half-point increments. A score of 10 is excellent, while zero indicates a diver completely failed.
Seven judges score individual competitions, and 11 are used for synchronized events (three score the execution of Diver A, three score the execution of Diver B, and the other five score the synchronization of the pair).
For individual dives, each judge awards a score, and the two highest and two lowest are tossed out. The remaining scores are added up and the total is multiplied by the degree of difficulty assigned to a particular dive to calculate the overall score. Degree of difficulty ratings range from 1.2 to 4.1 in one-tenth increments.
For synchronized dives, the highest and lowest execution scores for each diver are eliminated, as are the highest and lowest synchronization scores. The remaining scores are totaled and the sum is multiplied by the degree of difficulty assigned to a particular dive. This total is multiplied by 0.6 to calculate the overall score.
