doitsu

Doitsu is a Japanese term meaning "German" and is used to describe German origin or characteristics in various contexts. In everyday Japanese, it can refer to Germany, the German people, the German language, or things associated with Germany. The word is derived from the German word Deutsch and appears in phrases such as Doitsu-jin (Germans) or Doitsu-go (the German language). In non-koi contexts, doitsu serves as a neutral descriptor of German origin.

In koi carp keeping, Doitsu designates a class of koi with a scaleless body or with a row of large scales along the dorsal midline. Doitsu koi are believed to have originated in Europe, with Germany frequently cited, and were later introduced to Japan where they became a standard category in koi breeding and shows. The scale pattern is the defining feature, while the fish generally retains the typical fin structure and coloration of their non-Doitsu counterparts. Doitsu specimens tend to have a distinctive, smooth body appearance due to the sparse or absent lateral scaling.

Common Doitsu varieties include Doitsu Hariwake, Doitsu Kujaku, Doitsu Bekko, Doitsu Sanke, and Doitsu Matsuba. Across these forms, the key characteristic is the reduced or absent body scales, which contrasts with the densely scaled bodies of many traditional koi. The term is widely used in the koi hobby and competitive shows to describe this specific scaling pattern and its visual effect.