Groningen uses a simple ladder system, designed by Herman Hiddema.
All games in the ladder are played with full handicap. If a player wins, he earns a plus (+), if he loses he gets a minus (-). The pluses and minuses cancel out. Promotions and demotions are given when a player has reached a certain number of pluses or minuses.
The number of pluses or minuses to change rank is:
|rank range||+/- needed|
|21+ kyu||1 (every game changes the rank).|
|dan players||4 + their current dan rank|
In addition, players can request a new rank based on e.g. tournament performance.
Once per year, the ladder is reset, which is based on anchoring the dan players to their official rank.