Ok the chess.com main article says that Kramnik just won a big tournament with a score of 6.5/9, which is +4 or something. What does that mean? How does the scoring system for tournaments work?

1 point for a win, 0.5 points for a draw, 0 points for a loss.  It's also sometimes stated like +4 =5 -0 which means 4 wins, 5 draws, and 0 losses.

what does +4 mean though? Does the /9 mean that he played nine games?

Thanks for the help

Kramnik scored 6 1/2 points out of 9 points (1 point for win, 1/2 point fro draw, 0 point for loss).  The +4 is that he had 4 wins and no losses (the rest draws).  He won 4 games and drew 5 games for a total of 4 + 2.5 or 6.5 points  out of 9 games.

+4 means that he won four games. Most tournament accounts would report Kramnik's score as +2 meaning that with 6.5/9 (nine games, hence 9 is the best possible score), he is two over an even score of 4.5.

The /9 means he had the opportunity to play 9 games.

 

In my last tournament I had the opportunity to play three games. I missed the first round (granted a +0.5 "bye"), won the second round (+1.0), and won the third round (+1.0). So my final standing for the event was 2.5/3.0.

likesforests wrote:

The /9 means he had the opportunity to play 9 games.

 

In my last tournament I had the opportunity to play three games. I missed the first round (granted a +0.5 "bye"), won the second round (+1.0), and won the third round (+1.0). So my final standing for the event was 2.5/3.0.

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 Byes are not granted in round robin events, however. The Tal Memorial was a round robin--all players play all other players. One must play or forfeit, so the term opportunity, as you use it, seems misleading, although it reflects well the realities of the Swiss events that are the norm for hobby players.

6.5/9 means he had an opportunity to score 9 points and scored 6.5 points, which is very good, given the competition. He played 9 games, so if he had won them all he would have received 9 points. The +4 is based off of how far above or below an even score you are. An even score is reached if you win just as many games as you lose, or draw them all. So, the even score is always half of the total points; in this case 4.5. If he wins, he gets .5 more than a draw, right (1 for win .5 for draw). So each game he wins, he reaches a +1 score. So if he drew all his games and won one game, he would end up with 5/9; a +1 score. If he drew all his games and won four, he would receive a 6.5/9; a +4 score.  

4/9 = -1    0/9 = -9     9/9 = +9    6/9 = +3    etc.

"One must play or forfeit, so the term opportunity, as you use it, seems misleading, although it reflects well the realities of the Swiss events that are the norm for hobby players."

 

The word "opportunity" reflects the realities at every level. Consider  the world championship match Kramnik-Topalov, 2006. Kramnik's score of 8.5/16 means he had the opportunity to play 16 games. He did not, in fact, play 16 games.

Good bit about no byes in round-robin events. And it's true fewer opportunities are missed when big cash prizes are involved!

 likesforests wrote:

The word "opportunity" reflects the realities at every level. Consider  the world championship match Kramnik-Topalov, 2006. Kramnik's score of 8.5/16 means he had the opportunity to play 16 games. He did not, in fact, play 16 games.

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 My point was that he was required to play 12 games, chose not to play one (or was denied the opportunity to play it due to unreasonable restrictions), and thus forfeited that game. Thus, he was tied with the challenger after 12, and was required to play 4 additional games in which he prevailed.