Especially Kurodo dokoro, which governed important affairs of the state, issued many cho, and more and more official documents which should have been issued in other forms such as i, zi or fu were issued as cho.
特に蔵人所は国政の枢要の座したために多くの牒を発給し、次第に移や辞、符など本来は他の書式で出されるべき事例も牒で発給されるようになっていった。