Idiosyncrasies of Swiss Manager program

I saw some comments regarding the recently concluded 17th Chess Club Rapid. Three players tied for the first three places. Some wondored how Abdullah could have been awarded the first prize on tie-breaks. If you look at his opponents you will see that he actually has the worst Buchholz tie-break amongst the three players.

The majority of tournaments are run using a software called Swiss Manager. This piece of software works out the round by round pairings making the tournament director job much simpler and allows pairings to be posted much quicker. The software also works out the final standings and tie-breaks if needed (as well as a lot of other functions which I do not need to go into here).

Description of common tie-break systems
The TD chooses the tie-break systems that he/she wants to use when creating the tournament. There are many tie-break systems available. The most commonly used are the Buchholz (SK) and Sonneborn-Berger (SB) and the Progress or Cumulative . The Buchholz computes a score using the sum of the score of each of the opponents of a player. The Sonneborn-Berger is similar to Buchholz but uses a weighting, a win takes the full score of the opponent, a draw half of that and a loss is zero. The Progressive system takes the players current score at the end of each round and sums it.


There are weaknesses in the Buchholz and SB systems. If you are paired (usually in the first round) with an opponent who subsequently drops out or worse, never started the tournament, your tie-break will be negatively affected. You will be unfairly penalized through no fault of your own. There are attempts to address this by modifying the method of calculating the tie-break score in cases of unplayed games such as forfeits or walk-over. This variations are selected in Swiss Manager at the beginning of the tournament. They are refered to as Buchholz Tie-Breaks (variabel with parameter) and Sonneborn-Berger-Tie-Break variable.

These variables describe how unplayed games are computed for tie-break purpose. There are three variations -

a) using opponents actual points (this is the original Buchholz)
b) the game is treated as a draw for tie-break purpose but still using the opponent's points
c) the game is treated as a draw against the player himself (please note the italics because this will really surprise you later.

Analysis of 17th Chess Club top three players tie-break

TB1 is first tie break and TB2 is the second tie break. The tie breaks taken from chess results  (not shown in the picture but they are at the bottom of the web page) are -
Tie Break1: Buchholz Tie-Breaks (variabel with parameter)
Tie Break2: Sonneborn-Berger-Tie-Break variable

There is no way to tell which variable that the TD selected based on the posted results. We can deduce it with a little analysis on how Abdullah got his tie-break score since he had a walk-over in the first round.

The results of top three by round

Abdullah Che Hassan
Rd	Opponent	Opp Score	Result
1	Muhd Taufik Azman	0	1 (walkover)
2	Razali Hamzah	4	1
3	Muhd Syazwan Zulkifli	5	1
4	Norizzudin Afendi Norazman	4	1
5	Ahmad Fadzil Nayan	6	0
6	Nor Ilhamuddin Shaikh Ali	4	1
7	Mohd Saprin Sabri	5	1
Ian Udani
Rd	Opponent	Opp Score	Result
1	Nge Jia Xuan	4	1
2	Saharuddin Mappa	4	1
3	Nor Ilhamuddin Shaikh Ali	4	1
4	Nik Ahmad Farouqi Nik Abdul Aziz	4	1
5	Mohd Saprin Sabri	5	0
6	Kamaluddin Yusof	5	1
7	Ahmad Fadzil Nayan	6	1
Ahmad Fadzil Nayan
Rd	Opponent	Opp Score	Result
1	Kabir Singh	2	1
2	Izuddin Ahayat	4	1
3	Abdul Aziz Abdul Shukor	5	1
4	Ismail Ahmad	5	1
5	Abdullah Che Hassan	6	1
6	Mohd Saprin Sabri	5	1
7	Ian Udani	6	0

The tie-breaks works out like this -

Player	SK	SB	SK (variable)	SB(variable)
Abdullah Che Hassan	28	22	33.5	27.5
Ian Udani	32	27	32	27
Ahmad Fadzil Nayan	33	27	32	26

SK and SB is worked out by me while the SK (variable) and SB(variable) are taken from the chess-results as in the link I given above. Note that Fadzil opponent's results must be wrongly reported. because there is a one point difference between my computations and the published one.

For Abdullah the difference between the normal and variable SK are a massive 5.5 points. This can tell us what the TD selected as the variable which I worked out to be (c) above. Here is my analysis. His first round game is treated as a draw (irrelevant in Buchholz) against himself. So his first round Buchholz score is 6-0.5 which is 5.5. Total Buchholz (5.5+4+5++4+6+4+5) giving the total 33.5 which is consistent with the score published in chess results.

This is outrageous. Not only did he not have to exert himself in the first round to get the full point, he benefitted tremendously in the tie-breaks. If his opponent had turned up to play, Abdullah would have been third in the tie-breaks by the rules. I for one, find that extremely ironic.