Explanation of Swiss System Tournament (Braindamage hazzard)

Introduction
For easier explanation I will use term "player" as name for competitor. A "player" can also mean a team of more players.

Swiss System Tournament is very similar system to Round Robin (every player faces all other players). The problem with Round Robin is that once the tournament has big number of players, it will take significant time to play all the games, that is why we use Swiss System Tournament - players are matched against each other based on their current score, so you always face a player of the same skill as yours. There is a predetermined number of rounds, this is where the time is saved. Players never face the same opponent twice.

For winning, players are awarded points - we can use either 2 or 3 points for victory. For loss a players get nothing and for a tie players get 1 point. Let's count with 2 points per victory now.

Continue reading for more details.

Creating the bracket
The system requires there to be even number of players (8, 10, 12 etc.). Let's assume we have 12 players (named A to L)and we decided to play 6 rounds. In first round the players can be matched by a random draw or by matching same skills players (this is determined for example by player's overall rating or last-season standings - we can probably use PA 1v1 roster to determine the quality of players assuming players start to use it more).

Let's say we have players A-E to be very good, F-I to be average and J-L to be poor, sorted by their last-season standings, descending (so player C is better than player D). The round 1 would be like this:

Round 1

A vs B
C vs D
E vs F
G vs H
I vs J
K vs L​

Now that we have a bracket, the tournament can begin.

The tournament

A vs B - winner is A
C vs D - winner is D
E vs F - winner is F
G vs H - winner is G
I vs J - winner is J
K vs L - winner is K​

Player points after 1st round (numbers before slash is a player):

A| 2 points (won against B)
B| 0 points (lost against A)
C| 0 points (lost against D)
D| 2 points (won against C)
E| 0 points
F| 2 points
G| 2 points
H| 0 points
I| 0 points
J| 2 points
K| 2 points
L| 0 points​

Standings after 1st round:

1. A|2
2. D|2
3. F|2
4. G|2
5. J|2
6. K|2
7. B|0
8. C|0
9. E|0
10. H|0
11. I|0
12. L|0​

You must keep to sort players with the same score by their rank. Now it is easy to match players for 2nd round. Let's also add some winners here, I assume you are understanding person and I can speed up now.

A vs D - A wins
F vs G - G wins
J vs K - K wins
B vs C - C wins
E vs H -H wins
I vs L - L wins​

Standings after 2nd round:

1. A|4
2. G|4
3. K|4 (K is below G because his overall skill is less than G's)
4. C|2
5. D|2
6. F|2
7. H|2
8. J|2
9. L|2
10. B|0 (even B's overall skill is very high, he has zero points, so he is here!)
11. E|0
12. I|0​

We need to create round 3 now and let's put some results in.

A vs G - G wins
K vs C - K wins
D vs F - F wins
H vs J - J wins
L vs B - B wins
E vs I - E wins​

Still we can go place by place, there is no collision where two players would meet again.

Standings after 3rd round:

1. G|6
2. K|6
3. A|4
4. F|4
5. J|4
6. B|2
7. C|2
8. D|2
9. E|2
10. H|2
11. L|2
12. I|0​

Oki, lets make a next round and put in results, let's see what happens (my brains is getting hot because I am doing this all by hand without any software to proove to you that it is easy to understand. I have no prior experience with Swiss System until this moment).

G vs K
A vs F
J vs B
C vs D (WARNING, they already played together!) -> C vs E
D vs H
L vs I (WARNING, they already played together!) -> WARNING, no players left to match​

Here it starts to get shitty. We need to move them. So we need to start from the bottom, D needs to play with the closest same skill player, that would be L, and H can face I.

So it is:

G vs K - G wins
A vs F - A wins
J vs B - B wins
C vs E - E wins
D vs L - D wins
H vs I - I wins​

Standings after 4th round: (ouch my head now)

1. G|8
2. A|6
3. K|6
4. B|4
5. D|4
6. E|4
7. F|4
8. J|4
9. C|2
10. H|2
11. I|2
12. L|2​

My brain is hurting now. Oki, we need to do new matching now for the last round, fifth round.

G vs A (WARNING) -> G vs K (WARNING) -> G vs B
A vs K
D vs E
F vs J
C vs H
I vs L (WARNING) -> (WARNING)​

Need to rebuild. C vs I and H vs L.

G vs B - B wins
A vs K - K wins
D vs E - E wins
F vs J - F wins
C vs I - C wins
H vs L - L wins

Standings after 5th round:

1. G|8
2. K|8
3. A|6
4. B|6
5. E|6
6. F|6
7. C|4
8. D|4
9. J|4
10. L|4
11. H|2
12. I|2

Now this is the standings of the tournament. As you can see, there are ties both for 1st place and for 3rd place. Now the Tie-breakers come in.

Tie-Breakers
1. Did tied players face one another? If yes, who won earlier - wins.

Didn't tie break?

2. Who has more victories? (If there are tie matches, this can play a role). Who has more - wins.

Didn't tie break?

3. Sum score of their opponenets but discard the highest and lowest score.

Our example:
Did G and K battle? Yes. Who won? G did. G takes 1st place in the tournament, K is 2nd.

Now its gets ... my brain will overheat lol. The more rounds you have, the easier it is to determine the winner without ties.

There is now multiple players tied, we cannot used 1st tie breaker, we can use 2nd, this does nothing here. We need to use the 3rd tie breaker.

A matched: B, D, G, F, K = Sum of opponent points = 6 + 4 + 8 + 6 + 8 = we discard one lowest and one highest (4 and 8) that leaves us to = 6 + 6 + 8 = 20

E matched: F, H, I, C, D = 6 + 2 + 2 + 4 + 4 = discard 2 and 6 = 2 + 4 + 4 = 10

F matched: E G D A J that is 6 8 4 6 4 bla bla 4 6 6 = 16
B matched: A C L J G that is 6 4 4 4 8 brain hurt 4 4 6 = 14

A 4th
F 5th
B 6th
E 7th

If there happens to be a match, which I am not sure if can, I have no clue what to do next ))

Final note
My brain is damaged by doing all this by heart and hand and I have no clue what to say next. It is fairly easy to match the round and when there is a decent amount of the rounds to still save time but enough to have a clear standings, it is for sure a very good tournament system that could easily hangle dozens of players in PA matches.

When there is ties after final round, we can also make a final rounds. In our example there would be a mega finale between G and K. And third place would be played by elimination, the couples would be matched by random, for example A with F and E with B, winners are lets say F and B, they play and B is winner so he takes 3rd place. This is only needed for tournaments that of course have prizes for these places, if there is only a prize for 1st place, there is no need to determine a 3rd position.

I hope this little, simple, short and clear explanation helped you. Happy tournamenting!

Source
http://en.wikipedia.org/wiki/Swiss-system_tournament
http://en.wikipedia.org/wiki/Tie-breaking_in_Swiss_system_tournaments

Great explanation! Next time, don't overload your brain like that though, PA needs all the support it can get!

Just to add, this system is fairly used in chess tournaments (including in my college chess tournament)
They have specific softwares to do the arranging
most of them are free, the organizer should download it and have it ready for next tournament

Nice post Martenus

Wow great post. Makes sense now. Still seems a strange way to do an 8 team tournament.

Edit : forget that, confusion averted.

The following page contains the swiss tournament software (mostly free)

Nice nice, thanks, this will come in handy.

I'm most familiar with Swiss tournament systems from... well, MTG. But it's certainly robust enough for PA.

When I opened the page:
Adds! Adds Everywhere!
finding the real download button is a real challenge

Sorry for this s....t adds page. Next time I'll post the exact download link.

I'm going to talk to my old chess coach. He was one of Washington states vice Presidents of chess operations

He will definatelly have some good advice, let us know what does he tell you, I am interested

Um haven't got ahold of him yet. But, the example you showed is accelerated pairings for swiss I believe. Not standard. Accelerated works best for 32-8 players probably. Round Robbins for 4-8 and standard for 32+

Wait, accelerated? No, it shouldn't be.

Standard matching is like this:
Players:
1 Strongest
2
3
4
5
6
7
8
9
10
11
12 Weakest

Round 1:
1 vs 7 and 1 wins
2 vs 8 and 2 wins
3 vs 9 and 9 wins
4 vs 10and 4 wins
5 vs 11 and 5 wins
6 vs 12 and 6 wins

Round 2:
1 vs 4
2 vs 5
6 vs 9
3 vs 10
7 vs 11
8 vs 12

if you want me to continue I can but thats standard.

In standard swiss the people are divided by seed at start of the tournament. so 1-6 was the top half, and 7-12 was the bottom half. The two halves are matched together. and you do that every time with each round but in round 2 you do it two times. with everyone with 1 point and everyone with 0 points. seeds 1 and 2 should not play unless they are both the only 2 people with there amount of points.