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Named after Meijin, a title in Japanese Go.
The OGS Meijin title is a group Elimination tournament with Japanese scoring rules. The handicap class is played on 19x19 boards.
It starts on the 1st of February each year.
Named after Honinbo, a title in Japanese Go.
The OGS Honinbo title is a 3 round group McMahon tournament with Japanese scoring rules. The handicap class is played on 19x19 boards.
It starts on the 1st of April each year.
Named after Kuksu, a title in Korean Go.
The OGS Kuksu title is a League tournament with Japanese scoring rules. The handicap class is played on 13x13 boards.
It starts on the 1st of June and 1st of December each year
Named after Mingren, a title in Chinese Go.
The OGS Mingren title is a group Elimination tournament with Chinese scoring rules. The handicap class is played on 19x19 boards.
It starts on the 1st of August each year.
Named after Tianyuan, a title in Chinese Go.
The OGS Tianyuan title is a 3 round group McMahon tournament with Chinese scoring rules. The handicap class is played on 19x19 boards.
It starts on the 1st of October each year.
This was the format used for all of the first five tournaments before the titling system was introduced.
All dan players and previous finalists of both group elimination titles and the first 5 tournaments (class-specific, so full tournament results do not apply to the nines class and visa-versa), get a free bye to the second round. The handicap class is exempt from the bye system as all players should have an equal chance of success.
All tournament rounds are fully seeded double round-robins, with the top player (and in later rounds, occasionally top 2 players depending on number of groups) going through to the next round. In the event of a tie at the top of the group, all tied players progress.
The handicap draw will be performed in the same manner as the others, seeded to have a large distribution of player ability in the first round. All groups will be groups of 7 or as close to it as is sensibly achievable.
The winner of the title will be the winner of the final, tie-broken by the Sonneborn-Berger (sum of the scores of opponent's beaten). In the event of a complete tie the title will be shared.
Gold, Silver and Bronze trophies will be awarded to their respective positions Green trophies will be given to class finalists.
This is strictly not quite the system used in real life McMahon format tournaments, and probably shouldn't have the name, but the resemblance in style is close enough that it seemed appropriate to use it.
All groups will be sorted into groups of 5 players, seeded but with players of the same ability directly together (top 5 players in the top group, next 5 players in the next etc).
All players in the top group will start at 0 points, in each group below will start with 1 less point (-1 for the second group, -2 for the third group etc).
Each group will be a single round-robin with the higher score player as white. If players share the same score white will go to the higher rated player. Due to the nature of the way the group system is likely to work and the aim of the tournament with regards to rewarding the best even performance, there will be no handicapping of games in the main or nines classes.
At the end of each round, the groups are reseeded based on score (so a player in group 2 with 3 wins would end the round with a score of 2), tiebroken by Sum of Opponent's Scores.
At the end of three rounds in this format the top ranks will be given out based on McMahon score, tiebroken on Sum of Opponent's Scores.
The handicap class will be exactly the same but without grouping together players of similar ability. The groups will be drawn entirely at random for each round and the scores for everyone will start at 0 in the first round.
Groups will be of 5 players in the main and nines classes, and 7 players in the handicap class (to give more of an opportunity for a variability in score)
Because of the unknown numbers of players, some people in the bottom groups may find themselves in a group of 4. For each of these a free win will be awarded, so that 100% wins is still worth 4 points (range will be 4 -> 1 instead of 4 -> 0)
Gold, Silver and Bronze awards will be given out appropriately to those with the highest respective scores. Green awards will be given to those with a 70% winning percentage.
This will consists of a top group (championship division) of 8 players playing for the tournament trophy itself.
Below the championship division, the rest of the tournament will be designed as a tier-system, in a pyramid format (2 groups in tier one, 4 groups in tier two etc.) designed to keep the bottom divisions as close as possible to the top.
Each season, the bottom two players in any division will get relegated to the tier below, to be replaced by the winners of two of the divisions in the tiew below.
Newly entering players will be proportionally divided between the divisions below the championship division. The championship division will always consist of 8 players, the other divisions will be variable, though the aim will be keep the numbers in each division as close as possible to ensure that everyone gets to play approximately the same number of games.
Each division will be a double round robin.
Gold, Silver and Bronze awards will be given out to the top three positions, and green awards will be given out to the remaining finalists.
Due to some tournament formats giving rise to games between players of very varied skill levels, it has become appropriate to have an adjudication system designed to call a fair end to games that are both holding the rest of the tournament up and have, for the purposes of the game itself, already long finished. As such, the following 8 principles will make up the adjudication system: