Kinship Enrichment — Tier 3 Extensions#

Context#

The kinship redesign (Friday 11 April 2026) introduced composable properties (lineage, bloodDegree) and new types (uncle_aunt, cousin, customary_adoption) to the core schema. Cross-jurisdictional research covering 20+ legal traditions produced findings relevant to extensions beyond the 7 covered in Tier 1 and Tier 2.

This document captures those findings as a proposal for future enrichment. Each extension section describes what the research found, what the extension currently has, and what improvements would add value.

Priority order: Extensions are ranked by the value the kinship research adds — i.e., how much the research found that the extension doesn’t already capture.

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1. UK England & Wales — HIGH VALUE#

What the research found#

The Administration of Estates Act 1925 (s.46) defines a precise intestacy hierarchy that explicitly distinguishes whole blood from half blood at two levels:

1. Siblings of the whole blood and their issue
2. Siblings of the half blood and their issue
3. Grandparents
4. Uncles/aunts of the whole blood and their issue
5. Uncles/aunts of the half blood and their issue
6. Crown (bona vacantia)

This is one of only three jurisdictions (with Hong Kong and New Zealand) that the research identified as requiring the bloodDegree property at the uncle/aunt level. The distinction is not just terminological — whole blood takes absolute priority over half blood at each tier.

The Inheritance (Provision for Family and Dependants) Act 1975 allows claims by a broader set of people, but the extension already captures these via ifpa1975Eligible.category.

What the extension currently has#

• ifpa1975Eligible.category enum: spouse, former_spouse, child, child_of_family, maintained_person, cohabitant
• No intestacy hierarchy modelling
• No kinship degree or blood distinction

Proposed improvements#

1. Add intestacy hierarchy model. A intestacyDistribution property with a ranked array of heir tiers, each with a relationshipCategory and bloodRequirement (whole/half). This would make the AEA s.46 rules machine-readable:

   Tier	Category	Blood	Maps to core types
   1	spouse	n/a	relationship.json
   2	children and issue	n/a	parent_child_*, grandparent_grandchild
   3	parents	n/a	parent_child_*
   4	siblings_whole	whole	sibling
   5	siblings_half	half	half_sibling
   6	grandparents	n/a	grandparent_grandchild
   7	uncles_aunts_whole	whole	uncle_aunt + bloodDegree: whole
   8	uncles_aunts_half	half	uncle_aunt + bloodDegree: half
   9	crown	n/a	n/a

2. Document the bloodDegree connection. Add $comment explaining that English intestacy is the primary use case for the core bloodDegree property — implementers building English intestacy calculators should populate bloodDegree on all uncle_aunt kinship records.

3. Add statutoryLegacy amount tracking. The extension has survivingSpouseEntitlement but no structured field for the statutory legacy amount (currently £322,000 from 26 July 2023). This is adjacent to kinship — the amount determines how much the spouse receives before the kinship-based distribution kicks in.

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2. Hong Kong — HIGH VALUE#

What the research found#

The Intestates’ Estates Ordinance (Cap. 73) follows the English AEA 1925 pattern closely, including the whole blood / half blood distinction at sibling and uncle/aunt levels. The research also found:

• New Territories customary law (tso/tong ancestral trusts) — patrilineal clan membership determines succession to communal land
• Pre-1971 Chinese customary law (Marriage Reform Ordinance 1971) — for estates of persons who died or acquired concubines before 7 October 1971, Chinese customary law may still apply, including concubine children’s inheritance rights

What the extension currently has#

• localGrantTypes enum
• mpfNomination (pension nominations)
• survivingSpouseEntitlement (personal chattels, statutory legacy, residue)
• intestacyDistribution.issueDistribution (per_stirpes/per_capita)
• No kinship hierarchy, no blood distinction, no customary law handling

Proposed improvements#

1. Add intestacy hierarchy — same pattern as England & Wales with the whole/half blood tiers. Cap. 73 is substantively identical to AEA s.46 for this purpose.

2. Add newTerritoriesCustomaryLaw section:

   • tsoTongMembership (boolean) — whether the deceased was a member of a tso/tong
   • patrilinealSuccession (boolean) — whether patrilineal succession applies to communal land
   • notes (string) — for recording the specific tso/tong and land details

3. Add preReformCustomaryLaw section:

   • applicable (boolean) — whether pre-1971 Chinese customary law applies
   • concubineChildrenRecognised (boolean) — whether children of concubines have inheritance rights
   • notes (string)

4. Document bloodDegree connection — same as England & Wales.

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3. US Estate — HIGH VALUE#

What the research found#

• The Uniform Probate Code stops at the 2nd parentelic line (grandparents and their descendants = uncles/aunts/first cousins). Some states go further.
• Half-blood rules vary dramatically by state — the extension already has halfBloodRule enum (equal_to_whole_blood, half_share, excluded), which is excellent. But it only applies at the sibling level. Some states apply different half-blood rules at the uncle/aunt level.
• Louisiana forced heirship is unique in the US — the extension models this.
• Per stirpes variants (strict_per_stirpes, modern_per_stirpes, per_capita_at_each_generation) are already well-modelled.
• The retirementAccountRules.edbCategory enum already captures eligible designated beneficiary categories.

What the extension currently has#

• halfBloodRule (3 values) — but only for siblings
• perStirpesVariant (3 values)
• louisianaForcedHeirship
• electiveShareDetails
• retirementAccountRules with edbCategory
• No intestacy hierarchy by kinship degree
• No uncle/aunt/cousin classification

Proposed improvements#

1. Extend halfBloodRule scope. Currently applies implicitly to siblings. Add a $comment clarifying that:

   • Most states apply the same half-blood rule at all levels (siblings, uncles/aunts)
   • Some states (e.g., Florida) treat half-blood differently at the uncle/aunt level
   • Implementers should apply the halfBloodRule to uncle_aunt kinship records using the bloodDegree property

2. Add intestacyDepth property:

   • upcCompliant (boolean) — whether the state follows UPC’s 2nd parentelic limit
   • maxParentele (integer) — how many parentelic orders the state recognises (2 for UPC states, 3+ for states like California that go to great-grandparents)
   • laughingHeirCutoff (boolean) — whether the state limits inheritance to prevent distant relatives (“laughing heirs”) from inheriting

3. Add collateralHeirRules section:

   • cousinInheritance (boolean) — whether first cousins can inherit on intestacy
   • representationAtCollateralLevel (boolean) — whether per stirpes representation applies to uncles/aunts and cousins

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4. Scotland — MEDIUM VALUE#

What the research found#

Scotland has a distinct succession system from England & Wales:

• Legal rights are indefeasible claims that cannot be defeated by will:
  • Jus relictae/relicti: surviving spouse’s right to 1/3 (with children) or 1/2 (without) of moveable estate
  • Legitim: children’s right to 1/3 (with surviving spouse) or 1/2 (without) of moveable estate
• Prior rights: surviving spouse gets dwelling house (up to £473,000), furniture (up to £29,000), and financial provision (up to £50,000)
• Intestacy order: spouse → children → parents + siblings → grandparents → uncles/aunts
• Cohabitation claims under Family Law (Scotland) Act 2006 — the extension already handles these well

What the extension currently has#

Scotland is already one of the most detailed extensions (590 lines):

• legalRights with spouse and children shares
• priorRights with dwelling/furniture/financial thresholds
• cohabitationClaim with duration and deadline tracking
• freeEstateDistribution with ranked distribution
• croftingSuccession with specific Crofting Commission rules
• survivorshipDestinations

Proposed improvements#

1. Add kinship-specific $comments to freeEstateDistribution mapping the Scottish intestacy order to core kinship types:

   • Rank 1: children (parent_child_*)
   • Rank 2: parents and siblings equally (parent_child_*, sibling, half_sibling)
   • Rank 3: surviving spouse (if no rank 1 or 2)
   • Rank 4: uncles/aunts (uncle_aunt)
   • Rank 5: grandparents (grandparent_grandchild)
   • Rank 6: Crown

2. Document that Scotland does NOT distinguish whole/half blood at the uncle/aunt level (unlike England). Half-siblings inherit equally with full siblings. This is a key difference implementers need to know.

3. Add successionScotlandAct2016 section documenting the 2016 reforms that are partially in force and partially pending — the extension references deadline versions but doesn’t explain the substantive changes.

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5. Ireland — MEDIUM VALUE#

What the research found#

The Succession Act 1965 creates a distinctive system:

• Legal right share (s.111): spouse gets 1/3 (with children) or 1/2 (without) — cannot be defeated by will
• Section 117 claims: children can claim the court failed in its “moral duty” to provide for them — highly discretionary
• Capital Acquisitions Tax uses kinship-based group thresholds:
  • Group A (€335,000): child, minor child of predeceased child
  • Group B (€32,500): parent, brother, sister, nephew, niece, grandchild
  • Group C (€16,250): all others
  • These thresholds make kinship classification directly relevant to tax

What the extension currently has#

• spouseLegalRightShare
• section117Claim with claimant person IDs
• intestacyRules.distributionOrder enum: spouse_only, spouse_and_children, children_only, parents, siblings, next_of_kin
• capitalAcquisitionsTax with group thresholds
• section56Advancement for lifetime gifts

Proposed improvements#

1. Expand distributionOrder to include the full Irish intestacy hierarchy. Currently missing: nephews_nieces (siblings’ children inherit by representation), grandparents, uncles_aunts, first_cousins. The Irish hierarchy continues further than the current enum suggests.

2. Add catGroupMapping to capitalAcquisitionsTax — a structured mapping of kinship types to CAT groups:

   • Group A: parent_child_biological, parent_child_adopted, grandparent_grandchild (minor grandchild of predeceased child only)
   • Group B: sibling, half_sibling, uncle_aunt, cousin, grandparent_grandchild (adult grandchild)
   • Group C: all others This makes the tax calculation directly computable from kinship data.

3. Document that Ireland does NOT distinguish whole/half blood — siblings and their issue inherit equally regardless of blood degree.

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6. Canada — MEDIUM VALUE#

What the research found#

Canadian succession is entirely provincial, with significant variation:

• Ontario: Succession Law Reform Act — spouse + children share, then parents, then siblings, then nephews/nieces, then “next of kin” (broad)
• British Columbia: Wills, Estates and Succession Act — includes more distant relatives
• Alberta: dower rights (surviving spouse’s right to homestead)
• Quebec: civil law system (forced heirship, community property)
• Indigenous land succession under various treaty frameworks

What the extension currently has#

Very thin — only 209 lines:

• indigenousLandDetails with land type enum
• albertaDower with spouse and property references
• No intestacy hierarchy, no heir classification, no provincial variation

Proposed improvements#

1. Add province enum — the extension currently has no way to indicate which provincial law applies. Critical since every province has different intestacy rules. Values: all 13 provinces/territories.

2. Add intestacyRules section (paralleling Ireland’s pattern):

   • distributionOrder enum covering the common-law provincial pattern: spouse_only, spouse_and_children, children_only, parents, siblings, nephews_nieces, grandparents, uncles_aunts, crown
   • preferentialShare (money) — the amount the spouse receives before sharing with children (varies by province: ON $350,000, BC $300,000, etc.)

3. Add quebecCivilLaw section:

   • forcedHeirship (boolean) — Quebec has forced heirship for surviving spouse (family patrimony)
   • familyPatrimonyApplies (boolean)
   • notes (string)

4. Document kinship type mapping — $comment on any heir classification noting that Canadian provinces generally do NOT distinguish whole/half blood (unlike England).

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7. EU Succession — MEDIUM VALUE#

What the research found#

The EU Succession Regulation (Brussels IV, No 650/2012) primarily governs which country’s law applies in cross-border estates — it doesn’t define kinship rules itself. However, the forced heirship variants modelled in the extension directly depend on kinship classification:

• French réserve héréditaire: only descendants are reserved heirs (since 2006 reform — parents lost their reserved share)
• German Pflichtteil: descendants, parents, and spouse
• Italian legittima: spouse, children (including adopted), parents
• Spanish legítima: varies by region (2/3 in common civil, 1/4 in Catalonia, 1/3 in Basque, symbolic in Navarre)
• Polish zachowek: descendants, spouse, parents — 2/3 of intestate share (or 1/2 for others)

What the extension currently has#

• ForcedHeirshipVariant.model (7 values)
• SpanishRegionalRegime.region (7 values)
• No kinship classification for who qualifies as a forced heir

Proposed improvements#

1. Add protectedHeirCategories to ForcedHeirshipVariant — a $comment or enum documenting which kinship types qualify as forced heirs under each model:

   Model	Protected heirs
   french_reserve	descendants only (since 2006)
   german_pflichtteil	descendants, parents, spouse
   italian_legittima	spouse, children, parents
   scandinavian_laglott	descendants only
   dutch_deferred	children only (monetary claim, not share)
   polish_zachowek	descendants, spouse, parents
   swiss_pflichtteil	descendants, spouse (parents removed 2023)

2. Document the 2023 Swiss Pflichtteil reform — parents are no longer protected heirs. The Switzerland extension may already capture this but the EU extension should note it for cross-border consistency.

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8. Switzerland — LOW VALUE#

What the research found#

• Three parenteles only (no 4th order — unlike Germany)
• 2023 Pflichtteil reform removed parents as protected heirs
• Pflichtteil fractions: descendants 1/2, surviving spouse 1/2 (of statutory share)
• The extension already models Pflichtteil by heir class with statutory and forced share fractions

What the extension currently has#

• pflichtteil.protectedHeirs[].heirClass: descendant, surviving_spouse, parent
• Cantonal variation handling
• Matrimonial property regime enum
• Notarial will forms

Proposed improvements#

1. Update heirClass enum comment — note that parent is no longer a protected heir since the 1 January 2023 reform. The enum value should remain (for pre-2023 estates) but be documented as historical.

2. Add reformDate or $comment noting that the 2023 reform increased the freely disposable share from 3/8 to 1/2 (when there are descendants and a spouse).

3. Document three-parentele limit — $comment explaining that Swiss law stops at the 3rd parentele (grandparents and their descendants). No great-grandparents or great-uncles. If no one in three parenteles, estate goes to the canton. This is a key difference from Germany (unlimited Ordnungen).

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9. India (general) — LOW VALUE#

What the research found#

The India extension covers the multi-personal-law framework. Hindu succession is already handled by the hindu-succession extension. The research found:

• Christian succession (Indian Succession Act 1925): follows English pattern with some modifications
• Parsi succession: entirely distinct — daughters get half the son’s share, widow gets equal to a child’s share
• Goa civil code: Portuguese-derived, community of property, forced heirship for children

What the extension currently has#

• personalLaw enum (6 values)
• coparcenaryDetails (Hindu-specific, overlaps with hindu-succession)
• muslimSuccessionRules with school enum
• Property classification (ancestral/self-acquired/mixed)
• Succession certificate types

Proposed improvements#

1. Add parsiSuccessionRules section:

   • daughterShareFraction: always 1/2 of son’s share
   • widowShareFraction: equal to one child’s share
   • notes (string)

2. Add christianSuccessionRules section:

   • followsIndianSuccessionAct (boolean)
   • notes (string) — for recording any state-specific deviations

3. Remove coparcenary overlap — the coparcenaryDetails section duplicates content in the hindu-succession extension. Consider deprecating it with a $comment pointing to the Hindu extension.

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10. UAE — LOW VALUE#

What the research found#

The UAE operates a dual-track system:

• Sharia track: UAE Personal Status Law (Federal Law No. 28/2005) applies Islamic faraid to Muslim estates
• DIFC/ADGM track: non-Muslims can register wills under common law principles at the DIFC Wills Service Centre or ADGM
• Decree Law 41 (2022): allows non-Muslims to elect home-country law

The Islamic succession extension already handles faraid comprehensively. The UAE extension’s value is in modelling the choice of track, not the kinship rules themselves.

What the extension currently has#

• successionTrack enum (3 values)
• difcWill and adgmWill with type enums
• shariaFixedShares section
• expatriateHandling
• propertyTreatment by tenure type
• disputeResolution with forum enum

Proposed improvements#

1. Add $comment to shariaFixedShares linking to the Islamic succession extension for full faraid modelling. The UAE extension should not duplicate the heir classification — it should reference it.

2. Add homeCountryLaw section for Decree Law 41 elections:

   • electedCountry (string, ISO 3166-1 alpha-2)
   • electionRegistered (boolean)
   • registrationReference (string) This is kinship-adjacent — the election determines which succession rules (and therefore which kinship classifications) apply.

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Implementation Priority#

Extension	Value	Effort	Recommended timing
UK England & Wales	HIGH	Medium	Next sprint — bloodDegree showcase
Hong Kong	HIGH	Medium	With E&W (same intestacy pattern)
US Estate	HIGH	Medium	Standalone — complex state variation
Scotland	MEDIUM	Low	Quick — mostly $comment documentation
Ireland	MEDIUM	Low	Quick — CAT group mapping is high-value
Canada	MEDIUM	Medium	Needs provincial framework first
EU Succession	MEDIUM	Low	Quick — forced heir category mapping
Switzerland	LOW	Low	Quick — 2023 reform documentation
India	LOW	Medium	Parsi/Christian rules need research
UAE	LOW	Low	Quick — mostly cross-references

Suggested execution order:

1. England & Wales + Hong Kong together (same intestacy pattern, both need bloodDegree)
2. Ireland + Scotland + EU Succession + Switzerland (quick wins, mostly documentation)
3. US Estate (standalone, complex)
4. Canada (needs more design work for provincial variation)
5. India + UAE (lowest priority, least kinship-specific)

Research Provenance#

All findings derive from the cross-jurisdictional kinship research conducted on Friday 11 April 2026. Sources documented in docs/superpowers/specs/2026-04-11-kinship-redesign-design.md.