The metsuke were charged with the special duty of detecting and investigating instances of maladministration, corruption or disaffection anywhere in Japan, and particularly amongst the populace having status below the daimyō.
It could be said that the metsuke functioned as the Shogun's intelligence agency or as internal spies, reporting to the officials in Edo on events and situations across the country.
[2] The metsuke were charged with focusing on those ranking below daimyō-status; and their counterparts, the ōmetsuke, were responsible for supervising the activities of officials and members of the daimyō (feudal lords).
In the middle of the Edo period, the color of the messenger (the role of conveying the orders of the shogunate to the daimyo of the whole country) and the ceremonial officer in the palace (Edo Castle) became darker than the color of the conventional inspector, and it came to be regarded as an honorary or quiet position, and the hatamoto, who served as a town magistrate or account magistrate, became a position appointed in old age.
This term was used to designate those who bore a special responsibility for overseeing coastal waters, and by implication, for dealing with matters involving foreigners.
[6] In the video game Total War: Shogun 2, metsuke are agents tasked with imprisoning or executing operatives of enemy clans, particularly ninja, as well as with overseeing settlements to increase internal security and improve tax collection.