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http://www.clubxiangqi.com/?F=faqA score may be associated with 5 possible indicators to provide additional information about the score.
N (new): indicates that the player is new and the score is not stablized yet. The indicator is temporary and is removed once the number of games reaches 20.
U (unreliable): indicates that the score may not tell the true strength of the player. The person may chat via IM, or using a word processors, or web surfing, or doing some other tasks for an extended period of time while playing. You may have an easier time to beat a multi-tasking opponent, but you may also have to wait a longer time for the person to make moves. In rare cases, you may have a hard time beating an opponent armed with chess analyzing softwares. This indicator is temporary and is removed once the person is no longer distracted for some time.
S (senior): indicates that the person has played many games (1000+ games) and the score is stable. This is a permanent indicator.
M (master) and GM (grandmaster): indicate that the player is good. These are honorary indicators, as they do not provide additional information about the score. A score of 2000+ is labeled as M, and a score of 2250+ is labeled as GM.