secretly in Kanji

A low-ranking samurai who engaged in exploration under secret orders from his lord.
Generic term for detectives in the Edo period.
It’s also called Shinobi no mono, Ninja, and spies.

At first, Iga and Koga people were used for covert activities by the shogunate, but the 8th shogun Tokugawa Yoshimune reorganized the Ohiroshiki Igamono brought from Kishu into Oniwa. It was designated as Oniwaban and placed as an intelligence agency under the direct control of the shogun. In addition, subordinates of Metsuke, such as Kobito Metsuke and Kachi Metsuke, were secretly ordered to fly all over the country and infiltrate the public to gather information.
Japanese said “On mitsu”.