Book of Inheritance (Kitāb al-Farāʾiḍ)
Introduction
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Book of Inheritance
This discipline is the science of apportioning estates.

The causes of inheritance are three: blood relationship, marriage, and walāʾ (the bond created by manumission).

Heirs fall into three classes: 1) those who receive fixed shares, 2) agnatic heirs, and 3) uterine relatives. Those entitled to fixed shares are ten categories: the two spouses; the father and the mother; the paternal grandfather and the grandmother; the daughters; the granddaughters through a son; the sisters from every side; and the maternal half-brothers.

The husband takes one-half of the estate; if the deceased has a child or a grandson, however remote, his share is reduced to one-quarter. The wife—whether one or more—receives half of whichever of those two shares would belong to a husband: one-quarter when there are no descendants, one-eighth when there are.

Both the father and the paternal grandfather are allotted one-sixth as a fixed share when male descendants (sons or sons’ sons) exist. In the absence of descendants they inherit by agnation, and when only female descendants remain they take both a fixed share and the residue by agnation.

Section
The paternal grandfather, however remote, when inheriting together with full or paternal siblings, is treated as though he were one of the brothers. If the division by muqāsamah (sharing as a brother) gives him less than one-third of the estate, he is granted the full third. When a sharer with a fixed portion is present after him, he receives whichever is more advantageous of: muqāsamah, one-third of what remains, or one-sixth of the entire estate. If only one-sixth remains, that sixth is assigned to him, and the siblings are excluded—except in the Akdariyyah case. In that case the estate is not subjected to ʿawl (proportional reduction), and no fixed share is assigned to a sister in his presence except in that very circumstance.¹ Paternal siblings, if they alone inherit with him, are treated like full siblings; and if they are joined