Status of Bye for SOS

Javaness2 · #1

Recently this tournament called the World Amateur Go Championship took place, you may have heard of it before. As per normal, the tournament is run as a Swiss Competition. The first tiebreaker was SOS and the secondary tiebreaker seems to have been SOS-2 that is where we ignore the first 2 opponents. In this case 2 players couldn't make it to the tournament, although they were scheduled to play in round 1 instead they did not appear and their opponent had a walkover win. What should happen to SOS whenever you effectively have a bye.

I ask because maybe it could change the results. In Europe the most important places are from 3 to 10, because nobody ever finishes higher. (That's just a little joke by the way.) Anyway, Cornel Burzo finished in the seventh place, but he gets a SOS of 0 from his first round opponent. Is it fair? Should he instead get something like average strength of his other opponents, rounded down?
What is the most popular or respected approach for such a situation?

Code:

; TC[T170604B]
; CL[A]
; EV[38th World Amateur Go Championship]
; PC[CN, Guiyang]
; DT[2017-06-04,2017-06-07]
; HA[h9]
; KM[7.5]
; TM[80]
; CM[ (submitted by cieply)]
;.
;
Bai Baoxiang               8d CN  xxxx  8    8    8    42   18+/w   37+/b   4+/b    7+/w    6+/w    2+/w    9+/b    3+/b     |16249156
Lee Sang-bin               7d KR  xxxx  6    6    6    43   5+/b    34+/b   20+/w   8+/w    18+/w   1-/b    3-/w    6+/b     |18413219
Lai Yu-Cheng               7d TW  xxxx  6    6    6    40   31+/w   10-/b   38+/w   14+/b   13+/w   12+/b   2+/b    1-/w     |13650813
Ko Daniel                  7d US  xxxx  6    6    6    40   36+/b   11+/w   1-/w    19+/b   7-/b    14+/w   16+/b   24+/w    |17001193
Shusaku Sakamoto           7d JP  xxxx  6    6    6    40   2-/w    35+/b   21+/w   26+/b   8+/w    7+/b    6-/w    10+/w    |13449513
Ri Jin-ung                 7d KP  xxxx  6    6    6    39   44+/w   39+/b   9+/w    10+/b   1-/b    26+/w   5+/b    2-/w     |18425231
Burzo Cornel               6d RO  BaMa  6    6    6    37   0+      33+/b   22+/w   1-/b    4+/w    5-/w    11+/b   9+/w     |10325249
Chan Nai-San               7d HK  WCh   6    6    6    34   47+/b   32+/w   12+/w   2-/b    5-/b    24+/w   21+/w   13+/b    |14349742
Surin Dmitrij              6d RU  78SP  5    5    5    42   29+/w   19+/b   6-/b    22+/w   11+/w   10+/w   1-/w    7-/b     |10825254
Podpera Lukas              7d CZ  APWS  5    5    5    41   15+/b   3+/w    14+/w   6-/w    23+/w   9-/b    20+/b   5-/b     |13201914
Kraemer Lukas              6d DE  BN    5    5    5    38   16+/w   4-/b    36+/w   17+/b   9-/b    18+/b   7-/w    25+/b    |14698739
Lin Viktor                 6d AT  Go7   5    5    5    35   21+/w   23+/w   8-/b    20+/b   32+/b   3-/w    18-/b   28+/w    |14501256
Li Kwan-tao                5d AU  xxxx  5    5    5    35   14-/b   45+/w   33+/b   25+/w   3-/b    23+/w   17+/b   8-/w     |18450234
Tanapatsopol Vorawat       5d TH  xxxx  5    5    5    35   13+/w   38+/b   10-/b   3-/w    33+/b   4-/b    31+/w   20+/w    |17301240
Gong Yujie                 5d CA  xxxx  5    5    5    31   10-/w   31+/b   28+/w   23-/b   20-/b   30+/w   35+/w   21+/b    |18462235
Janssen Frank              5d NL  xxxx  5    5    5    31   11-/b   18-/b   44+/w   39+/b   36+/w   27+/b   4-/w    19+/w    |10298596
Garcia Emil                4d MX  xxxx  5    5    5    30   19-/b   46+/w   39+/w   11-/w   22+/b   31+/b   13-/w   18+/b    |15086841
Savolainen Javier-Aleksi   5d FI  HGK   4    4    4    42   1-/b    16+/w   27+/w   30+/b   2-/b    11-/w   12+/w   17-/w    |14001537
Sam In-Hang                5d MO  xxxx  4    4    4    37   17+/w   9-/w    29+/b   4-/w    25+/b   20-/w   22+/b   16-/b    |15013834
Lips Fabien                4d FR  75Al  4    4    4    37   35+/w   28+/b   2-/b    12-/w   15+/w   19+/b   10-/w   14-/b    |13798631
Xi Yue                     5d SG  xxxx  4    4    4    36   12-/b   24+/w   5-/b    34+/b   27+/w   32+/w   8-/b    15-/w    |16998872
Stankovic Mijodrag         5d RS  NiSt  4    4    4    31   42+/b   25+/w   7-/b    9-/b    17-/w   47+/w   19-/w   31+/w    |10313083
Ben-David Reem             4d IL  TAv   4    4    4    30   48+/w   12-/b   34+/w   15+/w   10-/b   13-/b   24-/b   32+/b    |14825580
Goetzfried Andreas         4d LU  Lux   4    4    4    30   34-/w   21-/b   48+/b   28+/w   41+/w   8-/b    23+/w   4-/b     |14033206
Mazille Felicien           1d CH  Ishi  4    4    4    30   43+/w   22-/b   40+/w   13-/b   19-/w   36+/b   29+/b   11-/w    |15625027
Vo Duy_Minh                4d VN  xxxx  4    4    4    29   30-/b   47+/w   41+/b   5-/w    39+/b   6-/b    0-      40+/w    |18425132
Romeika Ernestas           2d LT  Kaun  4    4    4    29   37+/w   30+/b   18-/b   32-/w   21-/b   16-/w   34+/b   33+/w    |15862759
Tsolmon Sansar             5d MN  Ulb   4    4    4    27   0+      20-/w   15-/b   24-/b   34+/w   37+/b   41+/w   12-/b    |13662825
Zhurakovskyi Bohdan        5d UA  Rivn  4    4    4    27   9-/b    43+/w   19-/w   33-/w   42+/b   40+/b   25-/w   35+/b    |12374461
Suc Timotej                3d SI  Ljub  4    4    4    27   26+/w   27-/w   32-/b   18-/w   47+/b   15-/b   37+/w   41+/b    |12533697
Soldan Leszek              4d PL  Wars  3    3    3    34   3-/b    15-/w   35+/w   40+/w   38+/b   17-/w   14-/b   22-/b    |10449560
Fitrah Faishal_Umar        3d ID  xxxx  3    3    3    34   41+/w   8-/b    30+/w   27+/b   12-/w   21-/b   0-      23-/w    |18474236
Mutabzija Zoran            2d HR  Zagr  3    3    3    32   40+/b   7-/w    13-/w   29+/b   14-/w   35-/b   43+/b   27-/b    |10249041
Gudmundsson Hallbjorn      2d IS  Reyk  3    3    3    31   24+/b   2-/w    23-/b   21-/w   28-/b   45+/w   27-/w   42+/b    |16937085
Flood Jostein              3d NO  Oslo  3    3    3    29   20-/b   5-/w    31-/b   46+/w   45+/b   33+/w   15-/b   29-/w    |10533369
Guerin Alan                1k NZ  xxxx  3    3    3    29   4-/w    44+/b   11-/b   43+/w   16-/b   25-/w   42-/w   46+/b    |18486237
Jadron Milan               1d SK  Brat  3    3    3    28   27-/b   1-/w    47+/w   41-/b   44+/b   28-/w   30-/b   45+/w    |10201653
Adal Birand                2d TR  Ank   3    3    3    27   45+/w   14-/w   3-/b    42+/b   31-/w   41-/b   40-/w   43+/w    |15250015
Bernardis Davide           2k IT  Rave  3    3    3    27   46+/b   6-/w    17-/b   16-/w   26-/w   42-/w   44+/b   48+/b    |17886946
Wang Fangfang              3d CN  xxxx  3    3    3    26   33-/w   42+/w   25-/b   31-/b   43+/b   29-/w   38+/b   26-/b    |18413230
Chung Chun-chen            3d MY  xxxx  3    3    3    25   32-/b   48+/b   26-/w   37+/w   24-/b   38+/w   28-/b   30-/w    |18498238
Rix Alex                   2d UK  WLon  3    3    3    25   22-/w   40-/b   46+/b   38-/w   29-/w   39+/b   36+/b   34-/w    |10262032
Garcia_Dl_Banda Ricardo    6k ES  NamB  2    2    2    24   25-/b   29-/b   45+/w   36-/b   40-/w   46+/w   33-/w   38-/b    |13633389
Brown Haraldo              3k AR  xxxx  2    2    2    23   6-/b    36-/w   16-/b   45-/b   37-/w   48+/b   39-/w   47+/b    |17298765
Reis Nelson                5k PT  Por   2    2    2    21   38-/b   13-/b   43-/b   44+/w   35-/w   34-/b   48+/w   37-/b    |14886102
Kristensen Lars            5k DK  KGK   2    2    2    20   39-/w   17-/b   42-/w   35-/b   48+/w   43-/b   47+/w   36-/w    |13998413
Gale Bob                   2d ZA  xxxx  1    1    1    25   8-/w    26-/b   37-/b   48+/w   30-/w   22-/b   46-/b   44-/w    |17650094
Dave Sandeep               6k IN  xxxx  0    0    0    21   23-/b   41-/w   24-/w   47-/b   46-/b   44-/w   45-/b   39-/w    |14801182

Uberdude · #2

Whilst not directly answering the question, I think a better way would be to avoid this situation entirely: take people out of the draw if they are not there at (or before) the start of round 1. I don't know if Cornel's scheduled opponent Pal Balogh didn't turn up, or turned up, lost, and then didn't play the rest of the tournament (probably the former, but given it was Pal there is some small chance of the latter). When I was there last year the Madagascan player didn't turn up (and again this year) but they kept him in the 1st round draw which hurts someone's SOS. What is the point of this, do they really think he will abseil into the tournament venue from a helicopter in the 15 minutes from game start time to when you lose by default? If you have not appeared at the tournament venue before the first round, I say take them out of the draw and avoid this mess altogether. There is usually a local 'ghost' player there to handle even/odd player situations (though I got the impression maybe they didn't want her to miss her games, but that's misplaced priorities over a real participant not getting a game in each round as happened last year).

Schachus · #3

the real best answer to this is imo that you should only count the best 7 of 8 opponents for SOS.

giving a bye some sort of an average is also unfair. To give you an example: I remember once playing a youth chess tournament. In this tournament, forfeited games counted like a draw for SOS(not for points, of course) (SOS is called "Buchholz" in chess, but it's absolutely the same thing). I was doing pretty badly and had (I believe) 2 out of 6 before the last round. There was one other person who also had the same score, but worse Buchholz(SOS).
Then in the last round, he got paired with the bye, whilst I had a actual opponent, fought hard and won. Nevertheless he overtook me, because the bye, having lost all its games by forfeit, counted like it scored 3,5/7 for SOS and my opponent counted for the 2/7 he actually had after losing to me. Of course we were both near the bottom of the table, so it wasnt so important, but similar things can also happen near the top.

Having the worst, or even the worst 2 opponents cut out from SOS solves the problem of weak round 1 opponents(especially in swiss rather than McMahon), or of byes, while also acknowledging that bye is in fact the easiest possible opponent and should not be counted higher than any actual opponent.

Javaness2 · #4

My expectation would also be that SOS in one of the forms where we remove a couple of opponents would be better in an 8 round tournament.

I checked the very exciting article http://www.fide.com/component/handbook/ ... ew=article they seem to say that is correct to assume that you should compensate for a bye by creating a virtual tournament performance for the AWOL player

Code:

 From July 1, 2012 the following system only applies:
(b)    For tie-break purposes all unplayed games in which players are indirectly involved (results by forfeit of opponents) are considered to have been drawn.
        For tie-break purposes a player who has no opponent will be considered as having played against a virtual opponent who has the same number of points at the beginning of the round and who draws in all the following rounds. For the round itself the result by forfeit will be considered as a normal result.
        This gives the formula:
        Svon = SPR + (1 – SfPR) + 0.5 * (n – R)
        where for player P who did not play in round R:
n = number of completed rounds
Svon = score of virtual opponent after round n
SPR = score of P before round R
SfPR = forfeit score of P in round R
Example 1: in Round 3 of a nine-round tournament Player P did not show up.
Player P’s score after 2 rounds is 1.5. The score of his virtual opponent is
Svon = 1.5 + (1 – 0) + 0.5 * (3 – 3) = 2.5 after round 3
Svon = 1.5 + (1 – 0) + 0.5 * (9 – 3) = 5.5 at the end of the tournament
Example 2: in Round 6 of a nine-round tournament player P’s opponent does not show up. 
Player P’s score after 5 rounds is 3.5. The score of his virtual opponent is:
Svon = 3.5 + (1 – 1) + 0.5 * (6 – 6) = 3.5 after round 6
Svon = 3.5 + (1 – 1) + 0.5 * (9 – 6) = 5.0 at the end of the tournament

Uberdude · #5

The last two WAGCs in China have used their peculiar swiss draw system (top 4 split to separate groups, rest is random) and I think they are resistant to listening to criticisms from Westerners saying they are better at draw systems, despite many players much preferring the draw at the WAGC in Bangkok (which was advised by some Europeans and used some form of McMahon*). At last year's WAGC the Korean player played a 5k from Ireland in the 1st round so his SOS sucked, luckily he ended up the only player on 7 wins so it didn't hurt him. Next year it's in Japan, I don't know what draw they will use or have typically in the past.

* EGD results has following note:

Quote:

Pairing for this WAGCC was done based upon the actual playing strength of the players and using MacMahon system.
This system will not change the winner or top 3 of the tournament but will give a more accurate ranking of the places 5 to 15.
The other advantage is that the lower ranked players will get more opponents of equal strength so that they will have more interesting games
This MacMahon system is widely used in Europe in the last 30 years and around 9500 tournaments have been played in Europe based on this principle including all major championships.

Maybe a 10 kyu from Timbuktoo getting the chance to play and crushed by a 8d from China is something you want for international mixing and funsies, but it's probably not a good idea if you want a better ordering of the top 10 places not heavily influenced by the luck of the draw.

Javaness2 · #6

Since you're determined to go off topic :salute:

Until there is an actual IGF rating system, I think that you will have some problems with creating a McMahon system that can be seen by all the participants as entirely fair. Unfortunately, it is pretty unlikely that there will ever be an IGF rating system, so you will always have a bit of a dilemma around whether or not a 7d is actually a 4d, and if a 4d is 2k. It probably would be great to have a system like this http://www.europeangodatabase.eu/EGD/To ... ey=W061022 - which is a McMahon using 3 bands. It would also be great if the IGF could ensure beforehand that the pairing system was actually announced.

Until an IGF rating system actually exists, I think that my preference for some McMahonite system over a Swiss would be pretty weak. The tournament is about deciding who gets the title of World Champion, and an 8 round Swiss does that job just fine. I don't know of any benefit that getting second or third place would afford*. In the countries like China, Japan, *Korea, those with chances of winning, I suspect they don't care about who comes second or third. They would probably be just fine with a knock-out tournament. I think I'm right in saying that the only reason a knock-out was abandoned was down to the bulk of the competitors who'd been flown in by JAL wanting (quite rightly) to get to play more than 1 game.

*Apart from in the EGF where they (today) use it as a selection criteria for a top event

Pio2001 · #7

Javaness2 wrote:

he gets a SOS of 0 from his first round opponent. Is it fair? Should he instead get something like average strength of his other opponents, rounded down?

It seems fair to me. The SOS measures how hard the tournament was for you. Winning against no one is not hard at all, hence the 0 points.

HermanHiddema · #8

An important related issue is how SOS is used for pairing.

When I played the KPMC last year, I noticed they used adjacency pairing, i.e. if a player needs to be paired up, take the player with the highest SOS, if one needs to be paired down take the one with the lowest SOS, and within a score group pair players with high SOS against high SOS and low SOS against low SOS.

This is exactly opposite to the practice of fold pairing usually used in Europe, where you pair highest SOS down, lowest SOS up, and within a group pair the highest SOS against the lowest SOS.

If you receive zero SOS from a BYE in the first round, then with adjacency pairing you will continually get weaker opponents due to your low SOS, and will have an easier time scoring more points, while with fold pairing you will continually get stronger opponents and have a harder time scoring more points.

The system described by Javaness with virtual opponents getting all draws for the remainder of the tournament sounds reasonable to me. Dropping one or more results for SOS calculation at the end of the tournament is also good, IMO.

Status of Bye for SOS

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