The term Kachi means lower class warriors who fought on foot. According to the modern military system, warriors who are allowed to fight on horseback (Umamawari and above) correspond to officers and Kachi correspond to noncommissioned officers. Kachi were categorized into shibun (soldiers who had the status of samurai) and strictly distinguished from ashigaru (common warriors) who had not the status of samurai. At the battle field, they fought as the forerunners of their lords and in peaceful time, they served as the guards (Kachi-gumi (Kachi teams)) of castles or engaged in administrative jobs (metsuke (police)) or subordinates of kanjo-bugyo (commissioner of finance) as middle class managers.
Ieyasu TOKUGAWA established nine Kachi-gumi (Kachi team) in 1603 as the organization of the Edo bakufu (Japanese feudal government headed by a shogun). Thereafter, the number of persons as well as that of teams was increased. During the period when the bakufu was stable, there were 20 Kachi teams under Kachigashira (superintendant of Kachi teams) and each team had two kumigashira (head of Kachi team) and 28 Kachi. Kachi were gokenin (immediate vassals of shogun) who were entitled to kuramai (rice preserved in the depository of bakufu) and their salary was 70 bales, the equivalent of annual rice stipend of five men. Their formal suit was noshime (a kind of kimono)/shiro-katabira (light white hemp garment) and their normal suit was a black crepe haori (Japanese half-coat)/hakama (pleated trousers) with no family crest. Their family status were initially gokenin (kakaezeki (the lowest rank of gokenin)), but it became fudai (the highest rank of gokenin) in 1862.