07a. Olympiad Pairing Rules

Annex D: Pairing Rules Approved by the 1980 General Assembly. Amended by the 1986, 1987, 1992 and 1993 General Assemblies. Approved by 1994 and 1998 Executive Council.
A. Basic Pairing System
1.	The basic pairing system shall be the Controlled Swiss System Pairings using Game Points for both Pairing and Scoring.
B. Odd Number of Participating Teams
2.	The organizing federation shall be entitled to enter a second team ("B" team). If there is an odd number of participating teams the organizing federation has the right to enter a third team ("C" team), in which case all points scored against the additional team shall be counted, whilst the C-team itself shall not appear in the final ranking list of all teams.
3.	If the "C" team is paired and plays round 1 it shall remain in the tournament to the conclusion even though a team or teams dropping out or a new team or teams arriving subsequently results in an odd number of teams still in competition.
C. Ranking of Teams for Pairing Purposes
4.	Obtain a list of all teams participating and full names of all players of each team three months before the start of the Olympiad. The list of names and the order of the players can be changed only with the approval of the President of FIDE.
5.	Record the FIDE rating of each team member having such a rating.
6.	Assign an arbitrary rating of 2000 to team members who have no FIDE rating.
7.	Rank all teams in order of the average of their 4 highest FIDE-rated players (men's teams) and in order of the average of their 3 highest FIDE-rated players (women's teams). The team with the highest average rating shall be assigned Pairing Number 1, the second highest, Pairing Number 2, etc.
8.	If two or more teams have the same average rating, rank them as to relative strength by consideration of all available information. In this case the following criteria in descendent priority will be used: 1. the rating of the fifth player of the men's team; for women's team the rating of the fourth player. 2. the rating of the sixth player of the men's team.
3.	the final rankings of the previous Olympiad.
4.
D. Number of Rounds
9.	14 rounds are recommended if there are 61 or more teams taking part. 13 rounds are recommended if there are 60 teams or less taking part. The team captains can agree to change the number of rounds to 14 to equalise the number of rounds in the men's and the wo-men's championships. With 14 rounds the recommended sequence of playing days is 6, 7, 1 or 7, 6, 1 requiring 14 playing days, 2 rest days and 1 day for arrival/departure for a total of 17 days. With 13 rounds the recommended sequence is 6, 6, 1 requiring 13 playing days, 2 rest days and 1 day for arrival/departure for a total of 16 days.
E. Byes
10.	If there is an odd number of teams a bye should be given to one team which arbitrarily would be credited with 2 game points (men's teams) and 1.5 game points (women's teams). The team given the bye in the first round would be that team which had the highest ranking number. For example: if there are 85 teams, then the team ranked as No. 85 would receive the bye in the first round. The team given the bye in subsequent rounds would be that team with the highest ranking number from the group with the lowest total number of game points. No team shall receive more than one bye.
F. Scoring unfinished games for pairing purposes
11.	Unfinished games shall be considered as draws for pairing purposes.
G. Tie Breaking
12.	The position of teams that finish with the same number of game points shall be determined by application of the following tie-breaking procedures in sequence, proceeding from (a) to (b) to (c) to (d) to the extent required: (a) by the sum of the game scores of all the team's opponents; (b) by the number of match points won; (c) by the sum of the game scores of all opponents defeated plus one half of the game scores of all the opponents with which a tied result was achieved. (d) by the sum of the game scores of all the team's opponents, excluding the two opponents who scored the highest number of game points and two opponents who scored the lowest number of game points.
H. General Pairing Regulations
13.	Assign a pairing number to each team as per Section C.
14.	(a) No team shall play the same opponent more than once. (b) A team having scored without playing will not receive a bye. This is the case when a team has received a bye due to an odd number of teams or when one of the opponent teams did not appear on time.
15.	The difference of the scores of two teams paired against each other should be 0 or, if this is not possible, as small as possible.
16.	Pairings shall be made from the top group down to, but not including, the middle group; then from the bottom group up to, but not including, the middle group, and finally the middle group. The middle group shall be defined as that group in which the median team in the standings is located. If there is an even number of teams being paired, the lower of the two middle teams shall be considered as the median team. Example: Suppose there are 88 teams: Place . . . 43 20.0 points 44 20.0 points Median team 45 19.5 points 46 19.5 points . . .
17.	(a) No team's board 1 color difference will become >+2 or <-2. (b) No team's board 1 will receive the same color three times in row.
18.	(a) If in an score group a complete pairing is only possible without applying rule 17, such a pairing will then be made. (b) If in an odd score group a complete pairing is only possible by choosing another floater, another floater will be chosen.
19.	After the team pairings have been made, colors shall be assigned based on giving priority to: (1) equalisation of colors on board 1 (regardless of who has played or is playing board 1 and regardless of what colors the particular player assigned to board 1 has had), and (2) alternation of colors on board 1. The colors on the remaining board shall alternate with the player on board 3 having the same color as the player on board 1.
20.	If both teams have had white the same number of times on board 1 and have had opposite colors on board 1 in the immediately preceding round the colors shall be assigned to board 1 to provide alternation for each team from the color it had in the previous round.
21.	If both teams have had white the same number of times on board 1 the colors shall be assigned to board 1 to provide the lowest sequence of the same color for both teams.
22.	If both teams have had white the same number of times on board 1 and have had exactly the same sequence of colors, then priority shall be given to (a) balancing the color on board 1 of the team with the higher ranked team, or (b) alternation of color on board 1 of the higher ranked team from the last round.
23.	If both teams have had white the same number of times on board 1 and have had exactly the same sequence of colors, and each team has had the same number of whites and blacks on board 1, then the color on board 1 of the higher ranked team shall be alternated from the last round.
24.	In the first round the color assigned to board 1 of the team ranked number 1 shall be selected by lot. All other odd numbers in the top half of the ranking list shall receive the same color in the first round on board 1 as the team ranked number 1.
I. Detailed Pairings Procedure Round 1 - 4
25.	If there is an uneven number of teams in a group in the top half of the score groups, the weakest rated team shall be dropped to the group immediately below and paired against the strongest rated team in that group, that it has not already played.
26.	If the group from which the weakest rated team has been dropped is such that a complete pairing of all remaining teams in the group cannot be made, then - instead of dropping the weakest rated team - the second weakest team in the group shall be dropped, etc.
27.	If the weakest rated team that is dropped to the group immediately below has already played every team in the group immediately below, then it shall be moved back to its original group and the second weakest team shall be dropped, etc.
28.	If every team in an odd numbered group in the top half of the score group has played every team in the group immediately below then the same procedure is followed as per rules 25, 26 and 27.
29.	If there is an uneven number of teams in a group in the bottom half of the score groups, the strongest rated team shall be elevated to the group immediately above and paired against the weakest rated team in that group, that it has not already played.
30.	If the group from which the strongest rated team has been elevated is such that a complete pairing of all remaining teams in the group cannot be made, then the second strongest team in the group shall be elevated, etc.
31.	If the strongest rated team that is elevated to the group immediately above has already played every team in the group immediately above, then it shall be moved back to its original group and the second strongest team shall be elevated, etc.
32.	If every team in an odd numbered group in the bottom half of the score groups has played every team in the group immediately above then the same procedure is followed as per rules 29, 30 and 31.
33.	To the extent possible, teams in the top half of any point group shall be paired in sequence against the teams in the bottom half of the same point group.
34.	For teams in the median group and higher, priority shall be given to first finding the correct pairing for the strongest team in that point group, etc.
35.	For teams below the median group, priority shall be given to first finding the correct pairing for the weakest team in a given point group, then the second weakest team in that point group, etc.
36.	Assuming 2N teams in a group, it is first attempted to pair the first team in the group with the N + 1 team. If that is possible, we are left with a subgroup of 2N - 2 teams. The same procedure is now applied to the subgroup. Wherever a match is not possible because the teams have already played each other, or the subgroup is unsolvable, the first team in the group (or subgroup) is matched with N + 2 (instead of N + 1), then N + 3, until 2N, and if still unsuccessful, against N-1, N-2, etc. In order to illustrate this procedure, suppose there are six teams in a group, 1 through 6. There will be 15 combinations of pairing within the group, in the following descending order of priority: (1) 1 x 4, 2 x 5, 3 x 6 (2) 1 x 4, 2 x 6, 3 x 5 (3) 1 x 4, 2 x 3, 5 x 6 (4) 1 x 5, 2 x 4, 3 x 6 (5) 1 x 5, 2 x 6, 3 x 4 (6) 1 x 5, 2 x 3, 4 x 6 (7) 1 x 6, 2 x 4, 3 x 5 (8) 1 x 6, 2 x 5, 3 x 4 (9) 1 x 6, 2 x 3, 4 x 5 (10) 1 x 3, 2 x 5, 4 x 6 (11) 1 x 3, 2 x 6, 4 x 5 (12) 1 x 3, 2 x 4, 5 x 6 (13) 1 x 2, 3 x 5, 4 x 6 (14) 1 x 2, 3 x 6, 4 x 5 (15) 1 x 2, 3 x 4, 5 x 6
38.	In any group below the median group priority shall be given to pairing the weakest team in the group and the same logic shall apply as outlined in rule 37 but in reverse order.
39.	If the top ranked team in a group (the strongest team) has played all the other teams in the same point group, priority shall be given to pairing this team against the strongest team in the next point group below that it has not already played. This applies to teams in the median group and above.
40.	For the similar case in a group below the median group the lowest ranked team (weakest team) in that point group that has played all other teams in the same point group, priority shall be given to pairing this team against the weakest team in the next point group above that it has not already played.
41.	For teams in the median group and above if the top ranked team in a group has played all the teams in its own point group and all teams in the point group immediately below it, its opponent shall be found by selecting the highest rated team in the group next below, that it has not already played.
42.	For the similar case of teams in a group below the median group if the lowest ranked team in that point group has played all the teams in the point group immediately above it, its opponent shall be found by selecting the lowest rated team in the group next above that it has not already played.
43.	The same pattern of pairings shall be followed in the case of other teams in a given point group in the groups below the median group that have already played all other teams in their own point group as has been followed in pairing rules 39, 40, 41 and 42.
44.	Priority shall be given to making a pairing of all teams in a single group with other teams in the same group before dropping a team to the group below (if not all, not necessarily the maximum). In all such cases the same general logic as detailed above shall be followed.
J. Detailed Pairing Procedure for Rounds 5-14.
45.	After the 4th round, teams in a score-group (including 'floaters' from another score-group) shall be arranged in the order of their Extended Buchholz (EB = sum of each team's + its opponents' scores). The team with the highest EB shall be No. 1 in the group. Teams with the same Buchholz shall be arranged in the order of their initial pairing numbers. Example: Order in Group Pairing Number Buchholz 1 8 24.5 2 3 23 3 5 23 4 11 22.5 5 11 22.5 6 7 21.5
46.	In each median score-group or higher, priority shall be given to pairing the highest team (i.e. the team with the highest EB) with the lowest team in that group that it has not already played. The second highest team shall be paired with the second lowest team, etc.
47.	To illustrate the procedure, suppose there are six teams in a score-group, ordered 1 through 6 as described in rule 45. There will be 15 combinations of pairing within the group, in the following descending order of priority. (1) 1 x 6, 2 x 5, 3 x 4 (2) 1 x 6, 2 x 4, 3 x 5 (3) 1 x 6, 2 x 3, 4 x 5 (4) 1 x 5, 2 x 6, 3 x 4 (5) 1 x 5, 2 x 4, 3 x 6 (6) 1 x 5, 2 x 3, 4 x 6 (7) 1 x 4, 2 x 6, 3 x 5 (8) 1 x 4, 2 x 5, 3 x 6 (9) 1 x 4, 2 x 3, 5 x 6 (10) 1 x 3, 2 x 6, 4 x 5 (11) 1 x 3, 2 x 5, 4 x 6 (12) 1 x 3, 2 x 4, 5 x 6 (13) 1 x 2, 3 x 6, 4 x 5 (14) 1 x 2, 3 x 5, 4 x 6 (15) 1 x 2, 3 x 4, 5 x 6
48.	If there is an uneven number of teams in a group, the same procedure is followed and the remaining team is floated to the next score-group (provided it is not a floater from another score-group) and is paired within this group according to the same procedure.
49.	To illustrate the procedure, suppose there are 5 teams in a group. There will be 15 combinations of pairing within the group, in the following descending order of priority: (1) 1 x 5, 2 x 4, 3-floater (2) 1 x 5, 2 x 3, 4-floater (3) 1 x 5, 3 x 4, 2-floater (4) 1 x 4, 2 x 5, 3-floater (5) 1 x 4, 2 x 3, 5-floater (6) 1 x 4, 3 x 5, 2-floater (7) 1 x 3, 2 x 5, 4-floater (8) 1 x 3, 2 x 4, 5-floater (9) 1 x 3, 4 x 5, 2-floater (10) 1 x 2, 3 x 5, 4-floater (11) 1 x 2, 3 x 4, 5-floater (12) 1 x 2, 4 x 5, 3-floater (13) 2 x 5, 3 x 4, 1-floater (14) 2 x 4, 3 x 5, 1-floater (15) 2 x 3, 4 x 5, 1-floater [If, for example, No. 2 is a floater from an upper score-group, pairings (3), (6) & (9) are not valid].
50.	If the group from which the floater has been dropped is such that a complete pairing of all remaining teams in the group cannot be made, or if the floater has already played every team in the next group, then the floater shall be moved back to its original group, trying the next possible pairing according to the order of priority. If a complete pairing of all teams in two adjacent groups cannot be made, then these two groups shall be considered as one group, and rules 45-49 shall accordingly apply.
51.	In any group below the median group priority shall be given to pairing the lowest team (i.e. the team with the lowest EB) in the group and the same pattern of pairing shall apply as outlined in rules 46-50 but in reverse order.
K. Supplementary Rules
52.	Only those teams who have two or more players present at 19:00 HRS the day before the start of round 1 (and the pairing committee has been notified of their presence) plus those teams who have given notification of their time of arrival and travel arrangements (and the pairing committee advised) shall be paired for the first round with the added provision that the travel arrangements must be such that the absent team or teams shall be able to be in the tournament room before the lapse of one hour after the start of the first round.
53.	Those teams who do not show up before the lapse of one hour after the start of the first round shall lose round 1 by a 0-4 score (men's teams) and by a 0-3 score (women's teams).
54.	Rules 52 and 53 may be overruled by decision of the FIDE President.
L. Mechanism for Making the Pairings
55.	The pairings are to be made by a committee of three, each from a different FIDE federation.
56.	In order to ensure that accurate results of the previous round's play are used in making the pairings for the subsequent round, the Tournament Director or his officially designated appointee shall provide the Chairman of the Pairings Committee with a signed summary of results as they are available. This summary shall be started as soon as the first game is finished and continuously kept up-to-date and available to the Pairings Committee. In particular a signed summary of results shall be printed at 21:30 HRS.
57.	The organizing federation shall supply secretarial help in the form of one person who shall be available for meeting with the committee at their request to record, type and duplicate the pairings and record and type for future reference a brief write-up as dictated by the Pairings Committee Chairman, which would cover specific decisions which were made during the pairing of the round in question, together with supporting logic for the decision made.
58.	Pairings shall be made by computer if a computer is available and if the computer program has been tested and approved by the chairman of the Pairings Committee. Computer terminals should be in a room near the playing hall and fully dedicated to the use of the Pairings Commit-tee as and when required. If a computer is used for preparing the daily bulletins of the game scores, a separate terminal in a separate room should be provided for those preparing the bulletin. The computer pairings do not have to be 100% in agreement with handmade pairings to be acceptable although if there is no difference between the outcome of the pairings made by the computer and those made (by hand) by the Pairings Committee the final decision lies with the Chairman of the Pairings Committee.
M. Schedule
59.	New rounds shall be played from 15:00 HRS.
60.	Pairings by country including allocation of colors shall be posted as soon as possible after the Pairings committee has finished of making the pairings
61.	The list of the players for a new round has to be submitted by the team captain between 10:30 and 11:00 hrs.
62.	Pairings by players shall be posted not later than 13:00 HRS in the tournament hall.
63.	No protest against the pairing shall be allowed.
N. Explanation and Example by IA Almog Burstein (ISR)B. Odd Number of Participating Teams
1.	The Swiss System has been used in the Chess Olympiads since Haifa 1976. During this period understanding and acceptance of this system has increased to a marked degree. There continue to be suggestions for changes and improvements, but most of these were not worked out in detail and not implemented for the Olympiads.
2.	As a member of the Pairings Committee for the 1976, 1978, 1980 & 1982 Olympiads (along with Committee Chairman P.G. Haley, Canada), I have repeatedly proposed that, within a given score-group, the Buchholz (sum of each team's plus its opponents' scores) be used in developing the pairings such that those with the highest Buchholz would meet those with the lowest. This has the advantage of ensuring that teams will have met more equal opposition over the course of the Olympiad than happens with the old system.
3.	In the Curitiba Congress, November 1993, the Olympiad Pairing Sub-Committee (C. Jarecki, Y. Matsumoto, R. Wade and myself) recommended, for the 1994 and 1996 Olympiads, that the pairings be based on the old rules for the first four rounds, and then, the new rules using the Buchholz rankings. The recommendation was approved by the Rules Commission and the General Assembly of FIDE.
4.	The current use of outdated ratings, especially for teams that are relatively inactive in the FIDE rating system, should be limited to the first four rounds; but thereafter only data of the Olympiad itself (i.e. Buchholz) should be taken into consideration in pairing the subsequent rounds.
5.	In order to demonstrate the new principle, let us look into the crosstable of the 1988 Olympiad after 13 rounds and make together the pairings for the final 14th round. The teams are arranged in accordance with the above new rule 37, that is by the total game-points (GP) and then by their Buchholz (PS = positions according to the Buchholz seeding).
6.	The first three pairings, according to whatever Swiss rules we use, are forced: URS - CSR, ENG - NED USA -HUN. The next team, PHI, being the only one with 31.5 points, if floated to the next score-group. According to the old rules it has to play YUG. Under the new rules we have to pair the teams within the following re-arranged score-group: 1. YUG 2. PHI 3. ISR
7.	The first priority should be given to pairing YUG-ISR, but since PHI is a floater from an upper score-group, we have to go on to the second priority, that is YUG-PHI, and float ISR to the next score-group. And now comes the big difference.
8.	Under the old system the teams in the 30.5 score-group were arranged in the order of their initial pairing numbers: 1. SWE - 09 2. ARG - 14 3. DEN - 19 4. IND - 21 5. CHI - 27
9.	ISR is paired with SWE, while the other two pairings are ARG - IND and DEN - CHI.
10.	Let us look again into the crosstable. ARG and IND had but little encounter with strong opponents (this is why they were Buchholz low-seeded). And yet, they were given, in the last round, a sizeable chance to overtake stronger teams, by facing relatively weak opponents (each other)!
11.	This pairing had a direct effect on the fact that ARG (beating IND 2.5-1.5) took tenth place, but was the only team, among the first twenty, that did not play any of the first nine teams (except URS to which it lost 0:4)!
12.	How should the teams be paired so as to ensure that the final results would reflect their actual strength more closely
13.	Under the new system the six teams in the score-group (including the floater) are arranged in the order of their Buchholz. In this case: 1. SWE 2. CHI 3. DEN 4. ISR 5. ARG 6. IND
14.	Now let us take the chart of rule 39: Combination (1) is not valid because DEN - ISR have already played. Combination (2) is not valid because CHI - ISR have already played. Combination (3) is not valid because ISR - ARG have already played. Combination (4) is not valid because DEN - ISR have already played. Combination (5) is not valid because CHI - ISR have already played.
15.	So, combination (6) is the one: SWE-ARG, CHI-DEN and ISR-IND. In these circumstances, SWE would have met a relatively weaker opponent, and justly so, having 'overexerted' itself in the preceding rounds.
16.	Using this principle throughout the tournament, while adhering to the old game - point system would give fairer and more satisfactory results.