also: よんだん
noun
fourth dan
Used in martial arts, go, shogi, and other ranking systems to denote the fourth level of mastery.
彼は柔道で四段を取得した。
He earned a fourth dan in judo.
囲碁の四段になるには何年もかかる。
It takes many years to reach fourth dan in go.
四 (four) + 段 (dan, rank). The term follows the standard numbering pattern for dan ranks.