Nidan

Nidan, written 二段 in kanji, means "second rank" or "second dan." It is a term used in several Japanese ranking systems to denote the second level of expertise, following shodan (first dan). The dan system is used in martial arts, board games, and other disciplines that adopt graded levels of proficiency. In many contexts, nidan signifies a middle-ranking stage indicating solid competence and experience beyond the initial black-belt level.

In martial arts, achieving nidan generally requires additional training time and the successful demonstration of refined technique, controlled application, and a broader understanding of theory and form. The exact criteria and testing procedures vary by style and organization; examples include judo, karate, kendo, aikido, and other traditional arts. After earning shodan, many schools continue to use a black belt for higher dans, including nidan, though some organizations differentiate ranks with belt stripes, patches, or other insignia to indicate the dan number.

Beyond martial arts, nidan appears in other Japanese ranking traditions, such as go (the board game) and shogi (Japanese chess), where it denotes the rank of a proficient player who has attained the second dan level. In these contexts, nidan likewise represents progression beyond initial levels and is part of a broader dan hierarchy used to categorize skill and experience.

Etymology and usage: dan means level or step, while ni means two; together 二段 conveys the concept of the second level. The term is widely recognized in East Asian martial and cognitive disciplines and is understood to indicate intermediate proficiency within a formal grading system.