How many primary lines (جهات) should be recognized when determining precedence among collateral relatives?
Chapter on Distant Kindred (Dhawu al-Arham)
Al-Mughni
Book of Inheritance Shares (Farā'id)
Primary text
The correct number of primary lines (جهات) is four: Paternity (Abuwwa), Sonship (Bunuwwa), Brotherhood (Ukhuwwa), and Maternity (Umuma). This alignment avoids the issue where recognizing the line of 'uncleship' (Umuma) as a fifth line would unjustly disqualify the daughter of a full maternal cousin by the daughter of a full cousin (due to differing lineage paths through the father and the grandfather). Excluding 'uncleship' as a separate line prevents the disqualification of the children of brothers and sisters by the daughters of paternal uncles and aunts.
Supporting text
Abu al-Khitab enumerated five lines (including Paternity, Maternity, Sonship, Brotherhood, and Uncleship), which leads to complications such as the daughter of a paternal cousin through the mother being disqualified by the daughter of a full cousin (through both parents). The better approach is four lines. If all relatives are considered one group inheriting based on who is nearest to the primary heirs, that is preferable.