This article is from the Go FAQ, by Morten PAHLE email@example.com with numerous contributions by others.
In Japanese, Kyu means 'step' and Dan means 'grade'. The idea is that
one must progress through several elementary steps before obtaining a
grade, and that there are several grades.
Therefore, several steps and grades exist. The scale starts around 30
Kyu (lowest) to 1 Kyu (highest) and then continues with 1 Dan (lowest)
to 7 Dan (highest). In addition, there are professional Dan ranks,
which run from 1 Dan professional (lowest) to 9 Dan professional
Unfortunately, the ranking system has no absolute values. (There are
no 'anchors'.) Therefore, a 1 Dan player in e.g. the U.S.A. is not
necessarily a 1 Dan player elsewhere. Traditionally, Japanese ranks
are considered weak, followed the U.S. rankings, with European
rankings being strong. (E.g. a European 1 Dan will be around 3 Dan US
and 5 Dan Japan). Rankings on the internet servers (see section 3)
also vary. IGS rankings are typically 3-4 stones stronger than
European rankings. E.g. our European 1 Dan will rank around 3 Kyu on
A 1 Dan (professional) would be the equivalent to approximately a 6
Dan European amateur, a 9 Dan (professional) would be the equivalent
to approximately a 9 Dan European amateur. An IGS 4d* (see section 7)
is probably around 1 Dan professional.
Every Go player has a ranking. Beginners typically start around 30
Kyu, but rapidly advance to around 15 Kyu, experienced players may
become 1 Kyu after a few years of playing, and then advance to
'shodan', or 1 Dan, and beyond.
See also section 4.3.