Editing Go ranks and ratings (section)

== Kyu and dan ranks ==
Traditionally, the level of players has been defined using ''kyu'' and ''dan'' ranks.<ref name="dankyu">{{cite web|url=https://sentego.net/go-ranking-and-rating-system/#Go_rankings_and_ratings|title=Go ranking and rating system explained|date=28 February 2019|website=Sentego}}</ref> Kyu ranks are considered ''student'' ranks.<ref name=gobondclass>{{cite web|url=http://gobond.nl/Generiek/ToonPagina.php?Pagina=14 |title=Classifiactie van spelers |author=Nederlandse Go Bond |access-date=2008-03-28 |url-status=dead |archive-url=https://web.archive.org/web/20130910232529/http://www.gobond.nl/Generiek/ToonPagina.php?Pagina=14 |archive-date=2013-09-10 }}</ref> Dan ranks are considered ''master'' ranks.<ref name=gobondclass /> Beginners who have just learned the rules of the game are usually around 30th kyu.<ref name=goranks>{{cite web | url = http://www.mechner.com/david/go/kyu.html | title = Go ranks | author = David Mechner | access-date = 2007-12-14 | archive-date = 2017-05-15 | archive-url = https://web.archive.org/web/20170515221637/http://mechner.com/david/go/kyu.html | url-status = dead }}</ref> As they progress, they advance numerically downwards through the kyu grades. The best kyu grade attainable is therefore 1st kyu. If players progress beyond 1st kyu, they will receive the rank of 1st dan, and from then on will move numerically upwards through the dan ranks.<ref name=goranks /> In martial arts, [[Shodan (rank)|1st dan]] is the equivalent of a [[Black belt (martial arts)|black belt]]. The very best players may achieve a ''professional dan rank''.<ref name=goranks />

The rank system is tabulated from the lowest to highest ranks:
{| class="wikitable"
!|Rank Type
!|Range
!|Stage
|-
|Double-digit ''kyu'' (級,급) (''geup'' in [[Korean language|Korean]])
|30–20k
|Beginner
|-
|Double-digit ''kyu'' (abbreviated: DDK)
|19–10k
|Casual player
|-
|Single-digit ''kyu'' (abbreviated: SDK)
|9–1k
|Intermediate amateur
|-
|Amateur ''dan'' (段,단)
|1–7d
|Advanced amateur
|-
|Professional ''dan'' (段,단)
|1–9p
|Professional player
|}
(There is also an amateur title of 8-dan and a professional title of 10-dan, but these are not the same as ranks.)

Although almost all organizations use this system, there is no universal calibration. The methods of awarding each of those ranks and the corresponding levels of strength vary from country to country and among [[Internet Go server|online Go servers]]. This means that a player who is considered to be a 2nd kyu in one country, may only be considered a 5th kyu in another.<ref name=RankCompare>{{cite web | url = http://senseis.xmp.net/?RankWorldwideComparison | title = Rank Worldwide Comparison | author = Sensei's Library }}</ref>

Differences in strength up to amateur dan level generally correspond to the level of handicap that would yield an even game between the two players. For instance, it is expected that a 3d player could give 2 handicap stones to a 1d player and win half of their games. In contrast, differences in professional ranks are much smaller, perhaps 1/4 to 1/3 of a handicap stone. There are some significant differences in strength between ordinary 9p players and the best players in the world because 9p is the highest rank possible, which may account for this variation.

===Origin===
The first Go ranks were given in 2nd century (CE) China, when [[Handan Chun]] (Chinese: [[wikt:邯郸|邯郸]][[wikt:淳|淳]]) described the [[9 Pin Zhi]] (九品制) ranking system in his book ''[[Classic of Arts]]'' (艺经).
From the early 17th century, the [[Japan]]ese formalised the teaching and ranking of Go.<ref name=sansa>{{Citation | author = GoGoD (Fairbairn & Hall) | title = Articles on Famous Players | chapter = Honinbo Dosaku | year = 2007 }}</ref> The system was later used in [[martial arts]] schools; and is thought to be derived originally from [[nine-rank system|court ranks]] in [[China]]. It is thought that the fact that there are 9 professional dan grades finds its base in the original 9 Chinese Pin Zhi grades.

===Achieving a dan rank===
''Dan'' (abbreviated online as "d") ranks are for advanced amateur players. Although many organisations let players choose their own kyu rank to a certain extent, dan ranks are often regulated. This means that players will have to show good results in tournaments or pass exams to be awarded a dan rank. Serious students of the game will often strive to attain a dan rank, much as martial arts practitioners will strive to achieve a black belt. For amateurs, dan ranks up to 7th dan are available. Above this level, a player must become a [[Go professional|professional player]] to achieve further promotions. In Japan and China, some players are awarded an amateur 8th ''dan'' rank as an honorary title for exceptional achievement.  In the United States, amateur dan ranks are often based on the AGA rating system. Under this system, some strong amateurs and former professional players have achieved up to 9th dan amateur, though generally they will register as 6th or 7th dan in international events. Similarly, some players have achieved 9th dan amateur ranks in the rating system of online Go servers.

Although players who have achieved professional dan ranks are nominally stronger than amateur dan players, in practice some of the strongest 7th dan amateur players have a playing level on par with that of some professional players. Such players have either never tried for a professional rank, or have chosen to remain amateur players because they do not want to make a career out of playing Go.

===Professional ranks===
{{Main article|Go professional}}
The professional dan ranking system is similar to that of amateurs in that it awards dan ranks that increase numerically with skill. The difference between these grades is much smaller than with amateurs however, and is not based on the number of handicap stones required. Professional dan ranks go up to 9th dan, but the strength difference between a 1st dan and a 9th dan professional is generally no more than 2–3 handicap stones.

To distinguish between professional ''dan'' and amateur ''dan'' ranks, the former is often abbreviated to "p" (sometimes called ''ping'') and the latter to "d". There was no such abbreviation in the past, and this is not generally used as an abbreviation beyond the Internet, where it is common, but not universal.