The Pandanet IGS Ranking System
The condition that the winner in a game with a player with a provisional rank or in Beginners Class has 50 points added to his or her rating points has been changed. (16 February 2009)
This is a rating system which is easy for all members to understand and accept and in which being able to calculate an accurate rating is a matter of course.
- The way ranks are expressed
- Addition and subtraction of rating points
- Promotion and demotion
- Beginners Class
- Ratings based on provisional ranks
- Games with special ratings
1. The way ranks are expressed
A player starts playing at the rank he or she declares (his or her provisional rank) and receives a certified rank after playing 20 rating games. The mark ”?” is applied to provisional ranks. Certified ranks vary by half ranks. Each rank is divided into two.
Examples of how ranks are expressed
|3d+||The top half of a certified 3d (equivalent to 3.5d)|
|3d||The bottom half of a certified 3d|
|3d?||A self-declared 3d (provisional rank)|
Rating games: Games with opponents with certified ranks are rating games.
However, the following games are excluded.
- Games on boards other than 19×19
- Games of less than two moves
- Games with professionals (whose ranks have “p” attached)
- Games with players in Beginners Class
- Games with opponents more than three ranks different in strength (games in which the handicap is correct for a difference of three ranks or less will be rated).
- Games in the “free play room”, the room for practice games with robots
- Pair Go games
Handicaps are calculated according to the chart below based on the difference in rank. These handicaps are called “the standard handicaps”. Previously, when there was a difference in ranks, the standard handicap was considered to be one stone per rank, but this is slightly favourable for White (the stronger player). By dividing each rank into two steps and changing the “standard handicap” to follow the chart below, it has been made possible to play games at a more appropriate handicap.
|Difference in rank||Handicap|
|0||No handicap stones, Black gives a komi of 6.5|
|0.5||No handicap stones, the weaker player (Black) gives a komi of 0.5|
|1||No handicap stones, the stronger player (White) gives a komi of 5.5|
|1.5||Two handicap stones, the weaker player (Black) gives a komi of 0.5|
|2||Two handicap stones, the stronger player (White) gives a komi of 5.5|
|2.5||Three handicap stones, the weaker player (Black) gives a komi of 0.5|
|3||Three handicap stones, the stronger player (White) gives a komi of 5.5|
|8.5||Nine handicap stones, the weaker player (Black) gives a komi of 0.5|
|9||Nine handicap stones, the stronger player (White) gives a komi of 5.5|
3. Addition and subtraction of rating points
Rating points are increased and decreased according to wins and losses in rating games. The change at the standard handicap is ±100 points. In games not played at the standard handicap, the changes, taking into consideration the handicap stones and komi, are as in the chart below.
|Rank difference considering handicap stones, komi||Stronger player wins||Weaker player wins|
|0 (Standard handicap)||100||100|
|3.5 or more||Not applicable to rating|
In cases besides even games (no handicap stones, komi 6.5), the rank difference is the figure with the handicap stones/komi subtracted from the actual rank difference.
Examples of calculating the rank difference
|White||Black||Actual rank difference||Handicap stones||komi||Rank difference considering handicap stones/komi|
|3d||1d||2.0||no||Black gives 0.5||1.5|
|3d||1d||2.0||2||White gives 5.5||0.0 (standard handicap)|
|4d+||1d||3.5||no||Black gives 0.5||3.0|
As previously, changes in the komi can be made by agreement between the players. One point of komi is converted to 1/2 of a rank, and calculations are made on a sliding scale from the above chart.
When the lower-ranked player (playing black) has set a number of handicap stones/komi exceeding the standard handicap, the player with black is considered the stronger player.
Also, when there are few rating games, the addition/subtraction of points per game will be expanded in accordance with the chart below in order to approach the proper rank sooner.
Scale of addition/subtraction per game
|No. of games||Points|
|0 – 20||Special calculation|
|21 – 50||150%|
|50 – 100||120%|
4. Promotion and demotion
Illustration of ranking promotion
Ranks change according to the addition and subtraction of rating points. At Pandanet, we used different ‘border zone systems’ for the promotion line and the demotion line. This enables players to enjoy their games without frequent rank changes near the rank borders.
5. The Beginners-Class
The lowest rank is 17k, but below there we have established a Beginners Class, referred to as BC.
In the Beginners Class, players are promoted to 17k after five wins regardless of their number of losses.
Conversely, when 17k drops below the demotion line, they are demoted to Beginners Class.
6. Self-estimated ranking
Concerning the first 20 games, a certified ranking is decided solely by the opponents’ ranks, the handicaps, and the results. The provisional ranking is automatically adjusted every five games according to the results to that point, but it can also be adjusted by the player.
7. Games with special ratings
The games in the cases specified below do not become rating games, but rating points may be added or subtracted.
- When the player does not making a greeting within one minute of the start of the game, it becomes a loss. This game does not become a rating game, but the winner is given 50 points and the loser is penalized 50 points.
- A game becomes no game if both players do not play the first move within one minute of the start of the game, including cases of resignation or being cut off. This game does not become a rating game, but the winner is given 50 points and the loser is penalized 50 points.
- Games with opponents with a provisional rating or in the Beginners Class are not included among the rating games, but the winner is given 50 points while the loser is not penalized. However, when the immediately preceding two games were not rating games, the 50-point addition is not applicable. Also, the 50-point addition is not applicable for players of 9k+ and up in games with players in the Beginners Class.