Iroquois kinship

Iroquois kinship (also known as bifurcate merging) is a system used to define. Identified by in his  work Systems of Consanguinity and Affinity of the Human Family, the Iroquois system is one of the six major kinship systems (,, , , , and ).

Kinship system
The system has both classificatory and descriptive terms. In addition to gender and generation, Iroquois kinship also distinguishes between parental siblings of opposite sexes. Parental siblings of the same sex are considered blood relatives (i.e., 'Parents'). However, parental siblings of differing sex are labelled as "Aunt" or "Uncle" as the situation necessitates. Thus, one's mother's sister is also called mother, and one's father's brother is also called father; however, one's mother's brother is called father-in-law, and one's father's sister is called mother-in-law.

Children of the parental generation (that is, children of parental siblings of the same sex) are considered siblings (s). The children of an Aunt or an Uncle are not siblings, they are instead cousins (s specifically).

Marriage
Ego (the subject from whose perspective the kinship is based) is encouraged to marry his s but discouraged from marrying his s. New  is constantly brought into the pool via Ego's father's sister's (Aunt's) husband or Ego's mother's brother's (Uncle's) wife. The system also is useful in reaffirming alliances between related or s.

Usage
The term Iroquois comes from the of northeastern North America. However, multiple groups around the globe employ the "Iroquois" system and is fairly commonly found in groups. These include:
 * 1) The entire population of ;
 * 2) The population of  and ;
 * 3) Most of the rural population of (wrong: this mode is right on the father's side; but all the mother's siblings' children are cousins).

South India and Sri Lanka
The entire population of, numbering in the vicinity of 250 million people, uses the kinship tradition described above. This includes not only the traditional encouragement of wedding ties between cross-cousins, but also the use of kinship TERMS in the following format:
 * One's mother's sister is also called mother, and her husband is called father;
 * One's father's brother is also called father, and his wife is called mother;
 * However, one's mother's brother is called father-in-law, and his wife is called mother-in-law; and,
 * One's father's sister is called mother-in-law, and her husband is called father-in-law

s are considered siblings, and it is forbidden for Ego to wed them. Cross cousins are however NOT siblings but termed Cousins; Ego may wed them.

China
Until recently, the same system was in use in rural societies.