"No student of Islamic inheritance can master the distribution of an estate without mastering the science of Hajb (Legal Exclusion). It is the jurisprudential filter that determines who inherits and who is barred by a closer relative."
In classical Arabic, the word الْحَجْب (Al-Ḥajb) linguistically signifies "to veil, prevent, screen, or obstruct." In the technical terminology of Islamic inheritance (Fiqh al-Farā’id), it refers to the legal prevention of a potential heir from receiving either their complete inheritance or their maximum fractional share, due to the presence of another relative closer in kinship to the deceased.
Classical masters of inheritance, such as Imam Siraj al-Din al-Sajawandi (author of Al-Sirājiyyah), emphasized that misapplying the rules of Hajb is the single most common cause of invalid estate distributions in the Muslim world.
1. The Two Cardinal Categories of Hajb
Islamic jurisprudence divides exclusion into two distinct operational categories:
An heir is not disinherited, but their fraction is demoted from a higher quota to a lower quota due to the presence of certain co-heirs.
Primary Classical Examples:
- Wife: Reduced from 1/4 to 1/8 when children or agnatic grandchildren exist.
- Husband: Reduced from 1/2 to 1/4 when children exist.
- Mother: Reduced from 1/3 to 1/6 by children or by two or more siblings of any kind.
- Son's Daughter: Reduced from 1/2 to 1/6 when one biological daughter is present (to complete the 2/3 female ceiling).
A potential heir is completely blocked from receiving any portion of the estate because a closer heir takes priority.
Primary Classical Examples:
- Son blocks Grandson: A living biological son completely disinherits a deceased brother's son.
- Father blocks Grandfather: The true paternal grandfather receives nothing when the father is alive.
- Mother blocks Grandmothers: A surviving mother bars all grandmothers (both maternal and paternal).
- Father or Son blocks Siblings: All brothers and sisters receive zero when a father or son survives.
2. The Six Inviolable Heirs (Never Blocked Totally)
In Islamic jurisprudence, there exists a sacred category known as: الْوَرَثَةُ الَّذِينَ لَا يُحْجَبُونَ حَجْبَ حِرْمَانٍ أَبَدًا "The heirs who are NEVER subject to total exclusion (Ḥajb Ḥirmān) under any circumstances."
Regardless of how many relatives survive or how distant or close the remaining family is, if any of these six individuals exist, they must receive their rightful inheritance. No other relative can ever completely extinguish their rights.
3. The Golden Canon: The Intermediate Link Rule
كُلُّ مَنْ أَدْلَى إِلَى الْمَيِّتِ بِوَاسِطَةٍ حَجَبَتْهُ تِلْكَ الْوَاسِطَةُ
"Whoever is related to the deceased through an intermediary is completely excluded by the presence of that intermediary."
This universal axiom governs most lines of succession. Because a grandson is connected to the grandfather through his father (the son), the existence of the son eliminates the grandson's right. Because the paternal grandfather connects to the deceased through the father, the living father blocks the grandfather.
4. Comprehensive Exclusion Hierarchy Matrix
The following reference matrix summarizes who blocks whom under standard Sunni jurisprudence:
| Dominant Heir (Blocker) | Heirs Completely Excluded (Blocked) | Jurisprudential Rationale |
|---|---|---|
| Son | Grandsons, Son's Daughters, Full Brothers, Full Sisters, Consanguine Siblings, Uterine Siblings, Nephews, Paternal Uncles, and Cousins. | A male agnatic descendant of the first degree takes absolute priority over collateral lines and lower descendants. |
| Father | Paternal Grandfather, Paternal Grandmother, Full Brothers, Full Sisters, Consanguine Siblings, Uterine Siblings, Nephews, and Uncles. | The direct male ascendant of the first degree terminates all ascendant claims through his lineage and shields the estate from collaterals. |
| Mother | Maternal Grandmothers and Paternal Grandmothers (unanimous for maternal; majority Sunni consensus for paternal). | Mother is the root origin; secondary roots (grandmothers) cannot inherit when the primary root is alive. |
| Two or more Daughters | Son's Daughters (unless assisted by an equal-degree male agnatic cousin/brother who acts as an Al-Mu'assib / Blessed Brother). | The Quran limits the collective maximum female descendant share to two-thirds (2/3). Two daughters fully exhaust this quota. |
| Full Brother | Consanguine Brothers, Consanguine Sisters, Nephews (brother's sons), and Paternal Uncles. | Stronger kinship: Full brother shares both father and mother with the deceased, taking precedence over paternal half-brothers. |
| Daughters + Full Sisters (Asabah ma'a al-Ghayr) | Consanguine Siblings, Nephews, and Paternal Uncles. | Prophetic Hadith: "Make sisters with daughters into residuaries" (Sahih al-Bukhari). A sister co-inheriting with a daughter acquires the strength of a brother, blocking lower collaterals. |
5. Crucial Distinction: Hajb vs. Disqualification (Māni‘)
One of the deepest technical subtleties in Fiqh al-Mawarith is the difference between a relative who is excluded by Hajb versus a relative who is disqualified by an impediment (Māni‘):
The Disqualified Person (Al-Mamnu‘)
A person barred due to a personal defect or crime (e.g., difference of religion/apostasy, or being the murderer of the deceased).
Rule: The disqualified person is treated as legally non-existent. They do NOT block or reduce anyone else. If a man dies leaving a Muslim mother and two non-Muslim brothers, the brothers cannot reduce the mother's share from 1/3 to 1/6.
The Blocked Person (Al-Maḥjūb)
A qualified Muslim relative who has no personal impediment, but is barred by another relative's closer presence.
Rule: The blocked person CAN still block or reduce others! If a deceased leaves a Father, Mother, and two Full Brothers: the Father totally blocks the Brothers from inheriting anything, yet the mere presence of those two blocked brothers reduces the Mother’s share from 1/3 to 1/6!
In FaraidCalc’s algorithmic logic, our calculation engine faithfully models this nuance, accurately tracking the active presence of siblings to compute the mother's partial reduction (Ḥajb Nuqṣān) even when the father absorbs the residuary balance.