Senmin (humble or lowly people) (賎民)
Senmin indicates a rank or a person of such rank who is placed lower than the common person.
Origin
It originated from a sense of vigilance to those different from oneself or the majority groups to which one belonged. Frequently, other people possessed languages and customs that were different than one's own. The ancient people felt they conveyed a sense of awe, as if they were untouchable by those who had different languages and customs.
In the agrarian society, a sense of vigilance was not raised toward the peasants, who possessed the same consciousness and standard of living as one's own. However, they recognized the non-peasants, as well as the unsettled entertainers and handicraftsmen, as people who lived in a special world that was different from theirs.
India
At the root of Indian society, there is the principle of Rinne Tensho (all things being in flux through the endless circle of birth, death and rebirth, or the circle of transmigration) in Hinduism. The Brahman, a clergyman who can unconditionally perform Rinne Tensho, is on top, and many common people who can perform Rinne Tensho with strict conditions (rituals) are slaves; there are two classes between them, which are the Royal Family and the common people (merchants), and in total these four classes comprise the caste system. Moreover, those who are supposed definitely not to be able to perform Rinne Tensho exist under these four classes as Senmin (outcasts). Shakyamuni appeared in such a society and preached that every one (including those whose occupations required that they take the lives of living things, such as stockbreeders and fishermen) could perform Rinne Tensho, to whom believers gathered. Therefore, it resulted in the phenomenon that there were many Buddhists among the people who were supposed to be Senmin. Furthermore, discrimination still deeply exists--even nowadays--toward the heretics who believe in the immortality of the spirit, such as in Christianity, and who believe in the spirits of ancestors, such as in Japanese Shinto.
(It is very difficult for Indians to understand that, in Japan, the ancestor worship of Shinto is mixed with Buddhism as 'my dear ancestors.')
Korea
Hakucho (the ordinary person or inferior servant) was placed in the lowest rank of the Senmin class.
Buddhist monks were also included in the eight Senmins of the Yi dynasty. They were not allowed to build even temples inside the castle of Hanyang (Seoul Special City). The descendants of powerful local clans (generals) defeated by the Yi dynasty were also included in Senmin. Its blood line is apparent instead of being ambiguous like the folklore of the fleeing Heike warriors in Japan.
Japan
The Nara period
Senmin was systematized in the Ritsuryo system (a system of centralized government based on the ritsuryo code). The people were divided into Ryomin (law-abiding people) and Senmin (Goshiki no sen, five lowly castes), and the obligations of So (rice), Yo (capitation), Cho (textile products), tax payment, and zoyo (irregular corvee) were imposed upon Ryomin, who were peasants. Senmin had none of the above obligations, but the Ryomin had no rights, and consequently those who chose to be free Senmin instead of inconvenient Ryomin appeared one after another.
The Medieval period
The abolishment of the Senmin system in the Nara period was followed by the collapse of the Ritsuryo system. However, the Senmin system based on Buddhistic thought appeared after that. Those who were related to the death of people and to the processing of dead livestock due to diseases, accidents, wars and others were defined as Senmin. Entertainers were called street performers and were also defined as Senmin, since they were considered pointless.
The Edo period
The Senmin class was placed outside the framework in the hierarchy of samurai, farmers, artisans and merchants.
However, there were also people of ambiguous existence such as fishermen and hunters, being described as 'in charge of butchery' in the 'village details' and others in each village, and therefore it wasn't possible to simply refer to them as being of the Senmin hierarchy. Moreover, the Imperial Family and court nobles weren't treated as Senmin, but some of the monks and priests were added to the Senmin category as kannagi or fugeki (female spiritual mediums). Occasionally the peasants and townspeople were distinguished from Senmin by collectively calling Heijin (common people).
The main regular occupations of Eta were the leather processing of dead livestock ('slaughter' was prohibited) as well as the management of footwear craftsmen and Hinin (a group comprising the lowest rank of Japan's Edo-period caste system). They did not belong to the lowest rank, but there was no opportunity to escape from it. There was a difference in the occupations depending on the period, and some of them managed to escape from Senmin at an early stage, such as well diggers, landscape gardeners, bathhouse, doctors, those who pled (lawyers), Noh performers (lead roles), Kabuki performers and blacksmiths. Some occupations were defined as Senmin depending on the region/period, such as various craftsmen (swordsmiths, masons, medicine peddlers, dyers, pen makers, wood cutters, armor makers, umbrella makers, sculptors of Buddhist statues and others), boatmen, Yin yang masters, astrologers, mountain priests, shrine priests, shrine maidens, dancing girls, dancers, musicians, Noh performers (minor roles), linked-verse poets, haikai poets, interpreters (translators), news-sheet sellers, and usurers (bankers).
Those who survived from joint suicide, persons of inbreeding, tax delinquents and street people accommodated by the authorities (including the sick) were placed in this rank of Hinin. Though they were at the bottom in the system of rank, occasionally an opportunity to escape (bail out) was given if it was within 10 years after becoming Hinin. However, for the one who was born as a child of Hinin there was no chance of escape. They were tattooed on the arm if they escaped from slave labor and were caught, and the number of escapes was recorded. Death was the sentence levied for three escapes. Hinin also had to undertake the role of prison administration. For a Heijin, the crime of killing one Heijin was equal to killing seven Hinins because of impertinence.
The recent period
The Senmin system in the Edo period was abolished after the concept of the "equality of all people" was introduced. However, a sense of discrimination toward Senmin was prevalent among the people, and the name "Shin-Heimin (new commoner)" was spontaneously established from Heimin (commoner). This influenced the problem of Buraku (hamlet) discrimination.
In the Edo period, a minimum of lifestyle stability was guaranteed by being given exclusive occupations such as the slaughter of livestock as well as leather craft and others. However, the modern equality of all people was only nominal and no specific measures were taken to dissolve it. Therefore, the transfer of employment to another industry sector wasn't a smooth process. On the other hand, some people started to newly enter the industry sectors that had once been occupied only by Eta, and consequently market competition emerged. As a result, there occurred the collapse of livelihood for many Senmin, thus contributing to the deepening of the Buraku discrimination problem.