As time went by, the part, sometimes, switched alternatively to the pro protagonists, or might be performed by some specialist called the "pro Noh chorus" during some transitional period and now, it has assumed the present form.
時代が下るにつれてシテ方と交替し、あるいは過渡期的に「地謡方」という専門の役職ができたりして変遷をたどりながら現在のかたちに落ちついたとされる。