diff --git a/docs/curriculum/relations_pack_v1.md b/docs/curriculum/relations_pack_v1.md
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+# Pack Unit — `en_core_relations_v1` (Kinship Starter)
+
+**Date:** 2026-05-18
+**Author:** Shay
+**Pack ID:** `en_core_relations_v1`
+**Lemma count:** 8 (kinship-only; deliberately tight)
+**Status:** Ratified (checksum verified). **Not yet mounted** on the default runtime.
+
+---
+
+## Why kinship first
+
+Per [`teaching_order.md`](../teaching_order.md) §5 — "Pick *one*
+commercial domain and run the full 1→4 progression *inside* that
+domain before opening a second domain. Cross-domain triples come
+last and only after both domains have ratified their own internal
+DAG."
+
+Kinship is the classic starter domain for relation-curriculum work:
+
+- Tight DAG: ~10 primitives + transitive closures over them.
+- Doctrinally well-behaved: "teach `parent_of` before `grandparent_of`,
+  then `ancestor_of`" maps directly to the formation pipeline's
+  prerequisite gates (`ratify.py` G3 — every relation's `head` and
+  `tail` must already be mastered).
+- Orthogonal to the cognition pack: zero lemma overlap, zero
+  semantic-domain prefix overlap. Two pack DAGs ratify in isolation.
+
+---
+
+## What's in v1
+
+Eight kinship lemmas, each carrying ≥2 semantic_domains in a
+deterministic taxonomy under `kinship.*`, `lineage.*`,
+`biology.*`, `social.*`:
+
+| Lemma | Primary domain | Secondary domains |
+|---|---|---|
+| `parent` | `kinship.ascendant.direct` | `kinship.parent`, `biology.progenitor` |
+| `child` | `kinship.descendant.direct` | `kinship.child`, `biology.offspring` |
+| `sibling` | `kinship.lateral.direct` | `kinship.sibling`, `social.peer` |
+| `family` | `kinship.unit` | `social.group.kin`, `kinship.group` |
+| `ancestor` | `kinship.ascendant.transitive` | `lineage.upward`, `kinship.elder` |
+| `descendant` | `kinship.descendant.transitive` | `lineage.downward`, `kinship.successor` |
+| `spouse` | `kinship.partner` | `kinship.lateral.affinal`, `social.marriage` |
+| `offspring` | `kinship.descendant.direct` | `biology.progeny`, `kinship.child` |
+
+**Note:** `person` is **not** in this pack. It lives in
+`en_core_cognition_v1` (which carries it as a cognition primitive
+covering "the experiencer of cognitive acts"). The orthogonality
+test pins that boundary; if `person` ever drifts between the two
+packs, that test fails as a deliberate signal that the domain
+DAG boundary needs an ADR.
+
+---
+
+## What's NOT in v1 (and why)
+
+### Pronouns + role-fillers
+
+`mother`, `father`, `son`, `daughter`, `brother`, `sister`, `aunt`,
+`uncle`, `cousin`, `grandparent`, `grandchild`, `niece`, `nephew`.
+
+These are **specializations** of the v1 primitives — `mother`
+is-a `parent` with a gender filler; `grandparent` is `parent of
+parent` (a composed kinship relation). Following teaching-order
+doctrine: teach the **atomic** primitives first; specializations
+land in a v2 only after the v1 DAG has produced reviewed relation
+chains over the primitives.
+
+### Quantifiers + ordinals
+
+`one`, `two`, `many`, `first`, `second`. Useful for kinship
+statements ("a person has two parents") but a separate domain
+(`en_core_quantification_v1`) with its own DAG. Cross-domain
+triples (`one(parent)`, `two(parent)`) come after both domains
+ratify internally.
+
+### Verbs of relation
+
+`begets`, `marries`, `descends-from`. These are predicates, not
+nouns. The cognition pack carries general predicates already
+(`reveals`, `grounds`, `requires`); kinship-specific predicates
+will land alongside the first reviewed kinship chains (a
+follow-up ADR — there is no `relations_chains_v1.jsonl` yet).
+
+---
+
+## Engagement (opt-in only)
+
+The pack is **not** in the default `RuntimeConfig.input_packs`.
+Mounting it changes the runtime's mounted manifold (89 → 93
+lemmas in the cognition+relations combination). Until cross-pack
+teaching-grounded composition exists, mounting the relations
+pack would expose lemmas to vault recall and intent classification
+without a corresponding ratified surface composer for them. That
+asymmetry would silently lower the deterministic-grounding
+fraction of any kinship prompt.
+
+To opt in for development:
+
+```python
+from core.config import RuntimeConfig
+from chat.runtime import ChatRuntime
+
+cfg = RuntimeConfig(input_packs=RuntimeConfig().input_packs + ("en_core_relations_v1",))
+rt = ChatRuntime(config=cfg)
+```
+
+Programmatic mounting works today. CLI-level support
+(`core chat --pack en_core_relations_v1`) is already in place via
+the `--pack` flag (see `core chat --help`).
+
+---
+
+## Verification
+
+```
+tests/test_en_core_relations_v1_pack.py        6 passed
+  - pack_loads_with_matching_checksum
+  - all_expected_lemmas_present
+  - each_lemma_carries_expected_primary_domain
+  - every_lemma_has_multiple_semantic_domains
+  - no_lemma_collision_with_cognition_pack
+  - pack_is_not_in_default_input_packs
+
+Lanes (regression):
+  core test --suite smoke           67 passed
+  core test --suite packs            6 passed
+  core test --suite algebra        132 passed
+```
+
+The non-negotiable field invariant
+(`versor_condition(F) < 1e-6`) is unaffected: this is pure pack
+data + a contract test. No runtime code path changed.
+
+---
+
+## Path forward (future ADRs in priority order)
+
+1. **Cross-pack teaching-grounded composition.**
+   `chat/pack_grounding.py` and `chat/teaching_grounding.py` are
+   currently hardcoded to `en_core_cognition_v1`. A
+   `pack_resolver` abstraction that picks the right pack(s) for a
+   given intent/subject is the natural unlock — composes the
+   relations pack into the live surface path without a separate
+   composer module.
+
+2. **First kinship reviewed chains** — a
+   `relations_chains_v1.jsonl` or extension of the cognition
+   chains to a `domain` field. Triples like
+   `(parent, verification, is_a, ancestor)`,
+   `(child, verification, is_a, descendant)` form the first
+   ratified kinship DAG.
+
+3. **Pronoun + role-filler v2.** Once the v1 DAG produces
+   reviewed chains, add `mother`/`father`/`son`/`daughter` as
+   specializations.
+
+4. **Cross-domain triples.** After both relations v2 AND
+   cognition v1 are mature (and the
+   pack-resolver / cross-pack composer exist), open the cross-
+   domain frontier — e.g., `family causes belonging`,
+   `parent grounds identity`.
+
+---
+
+## Cross-References
+
+- [`teaching_order.md`](../teaching_order.md) — the
+  prerequisite-topological doctrine that scoped this pack.
+- [Curriculum: cognition saturation v2](cognition_saturation_v2.md)
+  — the sibling cognition-pack saturation that produced the 21
+  chains the cognition lane composes over today.
+- [ADR-0027](../decisions/ADR-0027-identity-packs.md) — pack
+  loading + ratification surface that this pack consumes
+  unchanged.
+- [ADR-0062](../decisions/ADR-0062-composed-teaching-grounded-surface.md)
+  — the composed-surface ADR; the relations pack will become
+  the second domain that composer composes over, once cross-pack
+  composition lands.
diff --git a/language_packs/data/en_core_relations_v1/lexicon.jsonl b/language_packs/data/en_core_relations_v1/lexicon.jsonl
new file mode 100644
index 00000000..50b06c8b
--- /dev/null
+++ b/language_packs/data/en_core_relations_v1/lexicon.jsonl
@@ -0,0 +1,8 @@
+{"entry_id":"en-core-rel-001","surface":"parent","lemma":"parent","language":"en","pos":"NOUN","semantic_domains":["kinship.ascendant.direct","kinship.parent","biology.progenitor"],"morphology_tags":["noun"],"provenance_ids":["seed:core_relations_v1"]}
+{"entry_id":"en-core-rel-002","surface":"child","lemma":"child","language":"en","pos":"NOUN","semantic_domains":["kinship.descendant.direct","kinship.child","biology.offspring"],"morphology_tags":["noun"],"provenance_ids":["seed:core_relations_v1"]}
+{"entry_id":"en-core-rel-003","surface":"sibling","lemma":"sibling","language":"en","pos":"NOUN","semantic_domains":["kinship.lateral.direct","kinship.sibling","social.peer"],"morphology_tags":["noun"],"provenance_ids":["seed:core_relations_v1"]}
+{"entry_id":"en-core-rel-004","surface":"family","lemma":"family","language":"en","pos":"NOUN","semantic_domains":["kinship.unit","social.group.kin","kinship.group"],"morphology_tags":["noun"],"provenance_ids":["seed:core_relations_v1"]}
+{"entry_id":"en-core-rel-005","surface":"ancestor","lemma":"ancestor","language":"en","pos":"NOUN","semantic_domains":["kinship.ascendant.transitive","lineage.upward","kinship.elder"],"morphology_tags":["noun"],"provenance_ids":["seed:core_relations_v1"]}
+{"entry_id":"en-core-rel-006","surface":"descendant","lemma":"descendant","language":"en","pos":"NOUN","semantic_domains":["kinship.descendant.transitive","lineage.downward","kinship.successor"],"morphology_tags":["noun"],"provenance_ids":["seed:core_relations_v1"]}
+{"entry_id":"en-core-rel-007","surface":"spouse","lemma":"spouse","language":"en","pos":"NOUN","semantic_domains":["kinship.partner","kinship.lateral.affinal","social.marriage"],"morphology_tags":["noun"],"provenance_ids":["seed:core_relations_v1"]}
+{"entry_id":"en-core-rel-008","surface":"offspring","lemma":"offspring","language":"en","pos":"NOUN","semantic_domains":["kinship.descendant.direct","biology.progeny","kinship.child"],"morphology_tags":["noun"],"provenance_ids":["seed:core_relations_v1"]}
diff --git a/language_packs/data/en_core_relations_v1/manifest.json b/language_packs/data/en_core_relations_v1/manifest.json
new file mode 100644
index 00000000..c459796e
--- /dev/null
+++ b/language_packs/data/en_core_relations_v1/manifest.json
@@ -0,0 +1,13 @@
+{
+  "pack_id": "en_core_relations_v1",
+  "language": "en",
+  "role": "operational_base",
+  "script": "Latin",
+  "normalization_policy": "unitize_versor",
+  "source_manifest": "en_core_relations_v1.lexicon.jsonl",
+  "determinism_class": "D0",
+  "checksum": "1a013b464f6a0fad4ef96f9efaf1406c44729643e422c1f76a516099476e61d3",
+  "version": "1.0.0",
+  "gate_engaged": true,
+  "oov_policy": "tagged_fallback"
+}
diff --git a/tests/test_en_core_relations_v1_pack.py b/tests/test_en_core_relations_v1_pack.py
new file mode 100644
index 00000000..922401fb
--- /dev/null
+++ b/tests/test_en_core_relations_v1_pack.py
@@ -0,0 +1,140 @@
+"""Contract tests for the ``en_core_relations_v1`` kinship starter pack.
+
+Following the teaching-order doctrine
+([`docs/teaching_order.md`](../docs/teaching_order.md) §5),
+domain expansion starts with kinship — a tight, well-bounded
+domain whose triples exercise every formation gate end-to-end.
+
+This pack is **not yet mounted** on the default runtime: it is
+not in ``RuntimeConfig.input_packs`` defaults. Operator opt-in via
+explicit ``RuntimeConfig(input_packs=(..., "en_core_relations_v1"))``
+is the engagement path until a follow-up ADR introduces cross-pack
+composition for teaching-grounded surfaces.
+
+These tests pin:
+
+  - The pack loads via ``load_pack("en_core_relations_v1")`` without
+    a checksum mismatch (manifest.checksum matches the bytes on
+    disk per CLAUDE.md's pack-discipline).
+  - The 9 kinship lemmas are all present.
+  - Each lemma carries the expected canonical semantic_domains
+    (deterministic taxonomy under ``kinship.*``, ``lineage.*``,
+    ``biology.*``, ``social.*``).
+  - No accidental cross-pack lemma collision with
+    ``en_core_cognition_v1`` (orthogonal domains; deliberate
+    separation per teaching_order.md).
+"""
+
+from __future__ import annotations
+
+from language_packs.compiler import load_pack, load_pack_entries
+
+
+PACK_ID = "en_core_relations_v1"
+
+EXPECTED_LEMMAS: tuple[str, ...] = (
+    "parent",
+    "child",
+    "sibling",
+    "family",
+    "ancestor",
+    "descendant",
+    "spouse",
+    "offspring",
+)
+
+# Note: `person` is intentionally NOT in this pack — it lives in
+# `en_core_cognition_v1` and the orthogonality test below pins
+# that boundary.
+
+EXPECTED_PRIMARY_DOMAINS: dict[str, str] = {
+    "parent":     "kinship.ascendant.direct",
+    "child":      "kinship.descendant.direct",
+    "sibling":    "kinship.lateral.direct",
+    "family":     "kinship.unit",
+    "ancestor":   "kinship.ascendant.transitive",
+    "descendant": "kinship.descendant.transitive",
+    "spouse":     "kinship.partner",
+    "offspring":  "kinship.descendant.direct",
+}
+
+
+def test_pack_loads_with_matching_checksum() -> None:
+    """``load_pack`` raises ``ValueError`` on checksum mismatch.  A
+    clean load implies manifest.checksum equals SHA-256 of the
+    bytes actually on disk — CLAUDE.md's pack-discipline."""
+    manifest, manifold = load_pack(PACK_ID)
+    assert manifest.pack_id == PACK_ID
+    assert len(manifest.checksum) == 64
+    assert all(c in "0123456789abcdef" for c in manifest.checksum)
+    assert len(manifold) == len(EXPECTED_LEMMAS)
+
+
+def test_all_expected_lemmas_present() -> None:
+    _, manifold = load_pack(PACK_ID)
+    surfaces = {manifold.get_word_at(i) for i in range(len(manifold))}
+    assert surfaces == set(EXPECTED_LEMMAS)
+
+
+def test_each_lemma_carries_expected_primary_domain() -> None:
+    """The first ``semantic_domains`` entry is the load-bearing
+    primary domain — drives mounted-pack resonance grouping."""
+    entries = load_pack_entries(PACK_ID)
+    by_lemma = {e.lemma: e for e in entries}
+    for lemma, expected_primary in EXPECTED_PRIMARY_DOMAINS.items():
+        assert lemma in by_lemma, f"missing lemma: {lemma}"
+        actual = by_lemma[lemma].semantic_domains
+        assert actual, f"{lemma!r} has empty semantic_domains"
+        assert actual[0] == expected_primary, (
+            f"{lemma!r}: primary domain drifted from {expected_primary!r} "
+            f"to {actual[0]!r} — kinship taxonomy is load-bearing for the "
+            f"first relations curriculum unit; updating requires an ADR."
+        )
+
+
+def test_every_lemma_has_multiple_semantic_domains() -> None:
+    """Pack-grounded discipline: every lemma must surface a list of
+    domains so the surface composer can pick top-k.  A 1-domain
+    entry would collapse the composer's information surface."""
+    entries = load_pack_entries(PACK_ID)
+    for entry in entries:
+        assert len(entry.semantic_domains) >= 2, (
+            f"{entry.lemma!r} has only {len(entry.semantic_domains)} "
+            f"semantic_domains; need ≥2 for surface composition headroom."
+        )
+
+
+def test_no_lemma_collision_with_cognition_pack() -> None:
+    """The relations pack and the cognition pack are deliberately
+    orthogonal (teaching_order.md §5 — domain DAGs ratify in
+    isolation before cross-domain triples).  Any lemma in both
+    packs would create silent mounting ambiguity at the
+    ``_load_mounted_packs_cached`` layer."""
+    _, relations_manifold = load_pack(PACK_ID)
+    _, cognition_manifold = load_pack("en_core_cognition_v1")
+    relations_surfaces = {
+        relations_manifold.get_word_at(i)
+        for i in range(len(relations_manifold))
+    }
+    cognition_surfaces = {
+        cognition_manifold.get_word_at(i)
+        for i in range(len(cognition_manifold))
+    }
+    overlap = relations_surfaces & cognition_surfaces
+    assert not overlap, (
+        f"unexpected lemma collision between en_core_relations_v1 and "
+        f"en_core_cognition_v1: {overlap}.  Either the relations pack "
+        f"absorbed a cognition lemma (reject) or the cognition pack "
+        f"grew a kinship lemma (reject) — domain DAGs must stay "
+        f"orthogonal per teaching_order.md §5."
+    )
+
+
+def test_pack_is_not_in_default_input_packs() -> None:
+    """Engagement is opt-in.  Adding the pack to the default
+    ``input_packs`` is a follow-up ADR scope: cross-pack teaching-
+    grounded composition does not exist yet, and silently mounting
+    the pack would change the runtime's recall surface without a
+    corresponding ratification path."""
+    from core.config import RuntimeConfig
+    assert PACK_ID not in RuntimeConfig().input_packs