As well as seeking inside information of territorial lords for the Tokugawa shogunate, they kept peace of the Edo-jo castle town as doshin (a police constable) by handling surveys near the Edo-jo Castle, guard of O-oku (the inner halls of Edo Castle where the wife of the Shogun and her servants reside) and management of vacant residences.
彼らは、徳川幕府のために諸大名の内情を探るだけでなく、江戸城下の世論調査、大奥の警護、空き家となった諸屋敷の管理なども担当し、同心として江戸城下の治安の警護に当たった。