diff --git a/Z01_MasterData/Z01_MasterData_Router.py b/Z01_MasterData/Z01_MasterData_Router.py
new file mode 100644
index 00000000..e3e1e315
--- /dev/null
+++ b/Z01_MasterData/Z01_MasterData_Router.py
@@ -0,0 +1,29 @@
+"""Z01 마스터 데이터 라우터 — 읽기 전용(고치기는 다음 차례 · 2026-09-15 브레인).
+
+  GET /api/master-data/tree                                  갈래 → 파일 → 표
+  GET /api/master-data/rows?file=&table=&page=&size=&q=      표 줄(쪽 나누기 · 검색)
+⚠ 권한은 등록하는 쪽(`main.py` · 랩탑 서브)이 `dependencies=[verify_session, require_system_admin]` 로 붙임.
+"""
+
+from __future__ import annotations
+
+from fastapi import APIRouter, HTTPException
+
+from Z01_MasterData import Z01_MasterData_Tables as tables
+
+router = APIRouter(prefix="/api/master-data", tags=["Z01 MasterData"])
+
+
+@router.get("/tree")
+def get_tree() -> dict:
+    return tables.tree()
+
+
+@router.get("/rows")
+def get_rows(
+    file: str, table: str, page: int = 1, size: int = tables.DEFAULT_PAGE_SIZE, q: str = ""
+) -> dict:
+    result = tables.rows(file, table, page=page, size=size, q=q)
+    if result is None:
+        raise HTTPException(status_code=404, detail="없는 파일이나 표입니다.")
+    return result
diff --git a/Z01_MasterData/Z01_MasterData_Tables.py b/Z01_MasterData/Z01_MasterData_Tables.py
new file mode 100644
index 00000000..0779b85f
--- /dev/null
+++ b/Z01_MasterData/Z01_MasterData_Tables.py
@@ -0,0 +1,280 @@
+"""Z01 마스터 데이터 — `resources/` 마스터 JSON 을 **갈래 → 파일 → 표 → 줄** 로 가름(읽기 전용).
+
+마스터 = 로직 + 기초값(2026-09-15 사용자 방향 · bottom-up). 가르는 잣대 = 「값이 바뀌는 것 = 기초값 · 규칙·표 = 로직」(브레인).
+표 가르기(브레인 승인):
+  · `variables` 칸은 변수 하나 = 표 하나 — 변수 안에 목록이 둘 이상이면 한 표에 잇고 `@part` 열에 목록 이름
+  · 나머지는 줄 모음마다 표 하나 — 딕셔너리 목록 · 같은 길이 **수** 열(글 목록은 길이가 같아도 짝짓지 않음) ·
+    딕셔너리의 딕셔너리(`@key` 열) · 값 딕셔너리(`@key`·`@value` 줄)
+  · 설명(note·source·policy …)은 표가 아님 — 줄 안의 설명 칸은 그대로 둠
+한글 이름·단위는 **이름표 파일**(`resources/data_master_labels/*.json` · 데스크탑 서브 몫)에서만 — 없으면 영문 key.
+"""
+
+from __future__ import annotations
+
+import json
+import re
+from functools import lru_cache
+from pathlib import Path
+from typing import Any
+
+RESOURCES = Path(__file__).resolve().parent.parent / "resources"
+LABEL_DIR = RESOURCES / "data_master_labels"
+DEFAULT_PAGE_SIZE = 50
+MAX_PAGE_SIZE = 500
+
+# 갈래 나눔표(브레인 2026-09-15) — 차례가 화면 차례. 여기 없는 파일(강우 IDF 캐시 등)은 안 보임.
+GROUPS: tuple[tuple[str, tuple[str, ...]], ...] = (
+    ("logic", (
+        "pum_forest", "pum_const",  # 품셈 원문
+        "work_item_master",  # 공종 축
+        "coef", "material_surcharge", "formwork_reuse", "rebar_complexity", "timber_structure_class",
+        "masonry_class", "masonry_slope", "masonry_back_length", "stone_kind", "revetment_sabang",
+        "structure_unit_observed",  # 계수
+        "work_item_mapping", "aliases", "resource_catalog_ext",  # 잇는 표
+    )),
+    ("base", (
+        "labor_const", "labor_mfg", "mach_base", "machine_operating", "mat_price_public",
+        "oil", "oil_regional", "fx", "rates",
+    )),
+    ("byproduct", ("basis_missing", "form_undetermined", "resource_axis", "unmatched")),  # 정본 아님 — 기록
+    ("seed", ("masonry_wet",)),
+)  # fmt: skip
+
+# 파일 머리 — 표가 아님
+_HEAD_KEYS = {
+    "source", "sources", "policy", "derived_from", "source_dataset_version", "source_master_file",
+    "dataset_version", "stats", "master", "parse_audit", "variables",
+}  # fmt: skip
+_NOTE_KEYS = {"note", "notes", "source", "sources", "quote", "why", "policy"}
+_HIDDEN_KEYS = {"sha256", "generated_at", "raw_row_index", "sort_order"}
+_DATE_SUFFIX = re.compile(r"_\d{4}(?:-\d{2}-\d{2})?$")
+
+
+def _is_note(key: str) -> bool:
+    return key in _NOTE_KEYS or key.endswith("_note")
+
+
+def _scalar(v: Any) -> bool:
+    return not isinstance(v, (dict, list))
+
+
+def _flat(d: dict, prefix: str = "") -> dict[str, Any]:
+    """줄 하나 — 안쪽 딕셔너리는 `a.b` 열로 펼치고 목록은 값 그대로."""
+    out: dict[str, Any] = {}
+    for k, v in d.items():
+        if isinstance(v, dict) and v:
+            out.update(_flat(v, f"{prefix}{k}."))
+        else:
+            out[f"{prefix}{k}"] = v
+    return out
+
+
+def _list_rows(items: list) -> list[dict[str, Any]]:
+    return [_flat(x) if isinstance(x, dict) else {"@value": x} for x in items]
+
+
+def _numeric(v: Any) -> bool:
+    if isinstance(v, list):
+        return all(_numeric(x) and not isinstance(x, list) for x in v)
+    return v is None or (isinstance(v, (int, float)) and not isinstance(v, bool))
+
+
+def _columnar(d: dict) -> dict[str, list] | None:
+    """같은 길이 수 열(2개 이상) — 안쪽 한 겹 딕셔너리(`columns`)는 끌어올림."""
+    cols: dict[str, list] = {}
+    for k, v in d.items():
+        if _is_note(k):
+            continue
+        if isinstance(v, dict):
+            for ck, cv in v.items():
+                if _is_note(ck):
+                    continue
+                if ck in cols or not isinstance(cv, list):
+                    return None
+                cols[ck] = cv
+        elif isinstance(v, list) and k not in cols:
+            cols[k] = v
+        else:
+            return None
+    lengths = {len(v) for v in cols.values()}
+    if len(cols) < 2 or len(lengths) != 1 or 0 in lengths:
+        return None
+    if not all(_numeric(x) for v in cols.values() for x in v):
+        return None
+    return cols
+
+
+def _tableish(d: dict) -> bool:
+    """제 표로 떼어 낼 딕셔너리 — 같은 길이 수 열이거나 그런 것을 품음. 나머지는 한 줄로 펼침."""
+    return _columnar(d) is not None or any(
+        isinstance(v, dict) and _tableish(v) for k, v in d.items() if not _is_note(k)
+    )
+
+
+def _dict_rows(d: dict) -> list[dict[str, Any]]:
+    """목록 없는 딕셔너리 — 안쪽 딕셔너리는 키마다 한 줄(`@key` + 펼친 칸), 값은 키·값 줄."""
+    body = {k: v for k, v in d.items() if not _is_note(k)}
+    kv = [{"@key": k, "@value": v} for k, v in body.items() if not isinstance(v, dict)]
+    return kv + [{"@key": k, **_flat(v)} for k, v in body.items() if isinstance(v, dict)]
+
+
+def _variable_rows(v: Any) -> list[dict[str, Any]]:
+    if isinstance(v, list):
+        return _list_rows(v)
+    lists = [(k, x) for k, x in v.items() if isinstance(x, list) and not _is_note(k)]
+    if not lists:
+        cols = _columnar(v)
+        return [dict(zip(cols, r)) for r in zip(*cols.values())] if cols else _dict_rows(v)
+    consts = _flat(
+        {k: x for k, x in v.items() if not _is_note(k) and (_scalar(x) or isinstance(x, dict))}
+    )
+    # `key` = 어느 열이 키인지 적은 머리 — 줄 값이 아님
+    consts = {k: x for k, x in consts.items() if k != "key" and not _is_note(k.rsplit(".", 1)[-1])}
+    return [
+        {**consts, **({"@part": k} if len(lists) > 1 else {}), **row}
+        for k, items in lists
+        for row in _list_rows(items)
+    ]
+
+
+def _collect(node: Any, path: str, out: list[tuple[str, list[dict[str, Any]]]]) -> None:
+    if isinstance(node, list):
+        out.append((path, _list_rows(node)))
+        return
+    cols = _columnar(node)
+    if cols:
+        out.append((path, [dict(zip(cols, r)) for r in zip(*cols.values())]))
+        return
+    body = {k: v for k, v in node.items() if not _is_note(k)}
+    lists = {k: v for k, v in body.items() if isinstance(v, list)}
+    if lists:  # 목록마다 표 하나 · 곁의 값은 줄마다 붙임
+        consts = {k: v for k, v in body.items() if _scalar(v)}
+        for k, v in lists.items():
+            out.append((f"{path}/{k}", [{**consts, **r} for r in _list_rows(v)]))
+        for k, v in body.items():
+            if isinstance(v, dict):
+                _collect(v, f"{path}/{k}", out)
+        return
+    split = [k for k, v in body.items() if isinstance(v, dict) and _tableish(v)]
+    rest = {k: v for k, v in body.items() if k not in split}
+    if rest:
+        out.append((path, _dict_rows(rest)))
+    for k in split:
+        _collect(body[k], f"{path}/{k}", out)
+
+
+def file_id(path: Path) -> str:
+    return _DATE_SUFFIX.sub("", path.stem)
+
+
+def master_files() -> dict[str, Path]:
+    """갈래표에 든 id → 파일(같은 id 가 여러 판이면 이름 차례로 끝 판)."""
+    wanted = {i for _, ids in GROUPS for i in ids}
+    found: dict[str, Path] = {}
+    for p in sorted(
+        [*RESOURCES.glob("data_*/*.json"), *RESOURCES.glob("library_structure/*.json")]
+    ):
+        if file_id(p) in wanted and p.parent != LABEL_DIR:
+            found[file_id(p)] = p
+    return found
+
+
+@lru_cache(maxsize=64)
+def _tables_of(path: str, _mtime_ns: int) -> tuple[tuple[str, tuple[dict[str, Any], ...]], ...]:
+    data = json.loads(Path(path).read_text(encoding="utf-8"))
+    out: list[tuple[str, list[dict[str, Any]]]] = []
+    for name, v in (data.get("variables") or {}).items():
+        out.append((f"variables/{name}", _variable_rows(v)))
+    for k, v in data.items():
+        if k not in _HEAD_KEYS and not _is_note(k) and not _scalar(v):
+            _collect(v, k, out)
+    return tuple((tid, tuple(rows)) for tid, rows in out)
+
+
+def tables_of(path: Path) -> dict[str, tuple[dict[str, Any], ...]]:
+    return dict(_tables_of(str(path), path.stat().st_mtime_ns))
+
+
+def load_labels() -> dict[str, dict[str, Any]]:
+    """이름표 파일 모두를 한 벌로 — 부를 때마다 읽음(작은 파일 · 고치면 바로 보임)."""
+    merged: dict[str, dict[str, Any]] = {"groups": {}, "files": {}, "tables": {}, "columns": {}}
+    for p in sorted(LABEL_DIR.glob("*.json")) if LABEL_DIR.is_dir() else []:
+        data = json.loads(p.read_text(encoding="utf-8"))
+        for section, entries in merged.items():
+            entries.update(data.get(section) or {})
+    return merged
+
+
+def _text(entry: Any, key: str = "label") -> str:
+    if isinstance(entry, dict):
+        return str(entry.get(key) or "")
+    return str(entry or "") if key == "label" else ""
+
+
+def tree() -> dict[str, Any]:
+    labels = load_labels()
+    files = master_files()
+    groups = []
+    for gkey, ids in GROUPS:
+        entries = []
+        for fid in ids:
+            if fid not in files:
+                continue
+            entries.append(
+                {
+                    "id": fid,
+                    "label": _text(labels["files"].get(fid)) or fid,
+                    "key": files[fid].name,
+                    "tables": [
+                        {
+                            "id": tid,
+                            "label": _text(labels["tables"].get(f"{fid}/{tid}"))
+                            or tid.rsplit("/", 1)[-1],
+                            "key": tid.rsplit("/", 1)[-1],
+                            "row_count": len(rows),
+                        }
+                        for tid, rows in tables_of(files[fid]).items()
+                    ],
+                }
+            )
+        groups.append(
+            {"key": gkey, "label": _text(labels["groups"].get(gkey)) or gkey, "files": entries}
+        )
+    return {"groups": groups}
+
+
+def rows(
+    fid: str, tid: str, page: int = 1, size: int = DEFAULT_PAGE_SIZE, q: str = ""
+) -> dict[str, Any] | None:
+    """표 줄 한 쪽 — 없는 파일·표는 None. 검색은 줄 값 글자에 든 것(대소문자 무시)."""
+    path = master_files().get(fid)
+    table = tables_of(path).get(tid) if path else None
+    if table is None:
+        return None
+    columns: dict[str, None] = {}
+    for r in table:
+        columns.update(dict.fromkeys(r))
+    needle = q.strip().lower()
+    hits = (
+        [r for r in table if needle in json.dumps(r, ensure_ascii=False).lower()]
+        if needle
+        else list(table)
+    )
+    size = max(1, min(size, MAX_PAGE_SIZE))
+    start = (max(page, 1) - 1) * size
+    col_labels = load_labels()["columns"]
+    out_cols = []
+    for key in columns:
+        entry = col_labels.get(f"{fid}/{key}") or col_labels.get(key)
+        hidden = entry.get("hidden") if isinstance(entry, dict) and "hidden" in entry else None
+        out_cols.append(
+            {
+                "key": key,
+                "label": _text(entry) or key,
+                "unit": _text(entry, "unit"),
+                "hidden": bool(hidden)
+                if hidden is not None
+                else key.rsplit(".", 1)[-1] in _HIDDEN_KEYS,
+            }
+        )
+    return {"columns": out_cols, "rows": hits[start : start + size], "total": len(hits)}
diff --git a/resources/tester/test_z01_master_data.py b/resources/tester/test_z01_master_data.py
new file mode 100644
index 00000000..3fbd0891
--- /dev/null
+++ b/resources/tester/test_z01_master_data.py
@@ -0,0 +1,173 @@
+"""Z01 마스터 데이터 — 읽기 API(갈래 → 파일 → 표 · 표 줄 쪽 나누기·검색) · 2026-09-15 브레인 새 판.
+
+약속(브레인 승인): 갈래 넷 로직 17 · 기초값 9 · 부산물 4 · 씨앗 1 = 31 파일 · 강우 IDF 캐시는 뺌 ·
+variables 칸은 변수 하나 = 표 하나 · 나머지는 줄 모음(목록·같은 길이 수 열)마다 표 하나 · 설명(note·source·policy)은 표 아님 ·
+한글 이름은 이름표 파일(`resources/data_master_labels/`)에서만 — 찾는 차례 「파일id/열key」 → 「열key」 → 영문 key ·
+unit 도 이름표에서만(자료에서 지어내지 않음) · 숨김 = 내부 id · sha · 생성시각.
+"""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from Z01_MasterData import Z01_MasterData_Router as router_module
+from Z01_MasterData import Z01_MasterData_Tables as tables
+
+GROUPS = {
+    "logic": {
+        "pum_forest", "pum_const", "work_item_master", "coef", "material_surcharge", "formwork_reuse",
+        "rebar_complexity", "timber_structure_class", "masonry_class", "masonry_slope", "masonry_back_length",
+        "stone_kind", "revetment_sabang", "structure_unit_observed", "work_item_mapping", "aliases",
+        "resource_catalog_ext",
+    },
+    "base": {
+        "labor_const", "labor_mfg", "mach_base", "machine_operating", "mat_price_public", "oil", "oil_regional",
+        "fx", "rates",
+    },
+    "byproduct": {"basis_missing", "form_undetermined", "resource_axis", "unmatched"},
+    "seed": {"masonry_wet"},
+}  # fmt: skip
+
+
+@pytest.fixture
+def client(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> TestClient:
+    monkeypatch.setattr(tables, "LABEL_DIR", tmp_path / "labels")  # 이름표 없음 — 영문 key 그대로
+    app = FastAPI()
+    app.include_router(router_module.router)
+    return TestClient(app)
+
+
+def _tree(client: TestClient) -> dict:
+    res = client.get("/api/master-data/tree")
+    assert res.status_code == 200, res.text
+    return res.json()
+
+
+def _rows(client: TestClient, **params) -> dict:
+    res = client.get("/api/master-data/rows", params=params)
+    assert res.status_code == 200, res.text
+    return res.json()
+
+
+def test_갈래_넷에_파일_31_강우_캐시는_없음(client: TestClient) -> None:
+    groups = _tree(client)["groups"]
+    assert [g["key"] for g in groups] == ["logic", "base", "byproduct", "seed"]
+    for g in groups:
+        assert {f["id"] for f in g["files"]} == GROUPS[g["key"]], g["key"]
+        assert g["label"] == g["key"]  # 이름표가 없으면 영문 key
+        for f in g["files"]:
+            assert f["label"] == f["id"] and f["key"].endswith(".json") and f["tables"], f["id"]
+    ids = [f["id"] for g in groups for f in g["files"]]
+    assert len(ids) == 31 and not any("idf" in i or "rainfall" in i for i in ids)
+
+
+def test_variables_는_변수_하나가_표_하나(client: TestClient) -> None:
+    files = {f["id"]: f for g in _tree(client)["groups"] for f in g["files"]}
+    rates = [t for t in files["rates"]["tables"] if t["id"].startswith("variables/")]
+    assert len(rates) == 19, [t["id"] for t in rates]
+    vat = next(t for t in rates if t["id"] == "variables/rate_vat")
+    assert (
+        vat["key"] == "rate_vat" and vat["label"] == "rate_vat" and vat["row_count"] == 2
+    )  # rate_percent · base
+    assert len([t for t in files["coef"]["tables"] if t["id"].startswith("variables/")]) == 5
+    assert "processing_rules" in {t["id"] for t in files["rates"]["tables"]}  # 변수 밖 규칙도 표
+    # 한 변수에 목록이 둘이면 한 표에 잇고 어느 목록인지 열로 가름
+    fuel = _rows(client, file="mach_base", table="variables/mach_fuel_rate", size=500)
+    assert fuel["total"] == 214 + 21
+    assert {r["@part"] for r in fuel["rows"]} >= {"parsed_records"}
+
+
+def test_자재_단가는_쪽으로_나눠_주고_검색으로_좁힘(client: TestClient) -> None:
+    first = _rows(client, file="mat_price_public", table="variables/mat_price", page=1, size=50)
+    second = _rows(client, file="mat_price_public", table="variables/mat_price", page=2, size=50)
+    assert first["total"] == 6999 and len(first["rows"]) == 50 and first["rows"] != second["rows"]
+    assert {c["key"] for c in first["columns"]} >= {"item_code", "price_krw", "specification"}
+    assert "key" not in {
+        c["key"] for c in first["columns"]
+    }  # 「어느 열이 키인지」 머리는 줄 값이 아님
+    found = _rows(
+        client, file="mat_price_public", table="variables/mat_price", q="육각볼트", size=500
+    )
+    assert 0 < found["total"] < 6999
+    assert all("육각볼트" in json.dumps(r, ensure_ascii=False) for r in found["rows"])
+    capped = _rows(client, file="mat_price_public", table="variables/mat_price", size=100000)
+    assert len(capped["rows"]) == tables.MAX_PAGE_SIZE
+
+
+def test_같은_길이_수_열은_줄로_세움(client: TestClient) -> None:
+    slope = _rows(client, file="masonry_slope", table="table/메쌓기")
+    assert slope["total"] == 5 and slope["rows"][0] == {"성토": 0.3, "절토": 0.25}
+    wedge = _rows(client, file="masonry_wet", table="tables/고임돌표")
+    assert wedge["total"] == 7 and wedge["rows"][0]["keys"] == 25
+    # 글 목록 둘은 길이가 같아도 짝짓지 않음(자재 이름 ↔ 뒤진 자리)
+    files = {f["id"]: f for g in _tree(client)["groups"] for f in g["files"]}
+    ids = {t["id"] for t in files["material_surcharge"]["tables"]}
+    assert {"not_found/materials", "not_found/checked"} <= ids
+
+
+def test_원문_표는_번호로_찾음(client: TestClient) -> None:
+    hit = _rows(client, file="pum_forest", table="variables/pum", q="F0155")
+    assert [r["table_id"] for r in hit["rows"]] == ["F0155"]
+
+
+def test_내부_id_sha_생성시각은_숨김(client: TestClient) -> None:
+    axis = _rows(client, file="resource_axis", table="rows", size=1)
+    hidden = {c["key"]: c["hidden"] for c in axis["columns"]}
+    assert hidden["raw_row_index"] is True and hidden["resource_name"] is False
+    master = _rows(client, file="work_item_master", table="work_items", size=1)
+    assert {c["key"]: c["hidden"] for c in master["columns"]}["sort_order"] is True
+    assert all(c["unit"] == "" and c["label"] == c["key"] for c in axis["columns"])  # 이름표 없음
+
+
+def test_이름표_파일이_있으면_label_unit_을_붙임(client: TestClient, tmp_path: Path) -> None:
+    labels = tmp_path / "labels"
+    labels.mkdir()
+    (labels / "labels.json").write_text(
+        json.dumps(
+            {
+                "groups": {"base": "기초값"},
+                "files": {"rates": "요율"},
+                "tables": {"rates/variables/rate_vat": "부가가치세"},
+                "columns": {
+                    "base": {"label": "밑수"},
+                    "rates/rate_percent": {"label": "요율", "unit": "%"},
+                    "rate_percent": {"label": "딴 이름", "unit": "딴 단위"},
+                },
+            },
+            ensure_ascii=False,
+        ),
+        encoding="utf-8",
+    )
+    base = next(g for g in _tree(client)["groups"] if g["key"] == "base")
+    rates = next(f for f in base["files"] if f["id"] == "rates")
+    assert base["label"] == "기초값" and rates["label"] == "요율"
+    assert (
+        next(t for t in rates["tables"] if t["id"] == "variables/rate_vat")["label"] == "부가가치세"
+    )
+    cols = {c["key"]: c for c in _rows(client, file="rates", table="variables/rate_vat")["columns"]}
+    assert cols["@key"]["label"] == "@key"  # 없는 것은 영문 key
+    vat = _rows(client, file="rates", table="variables/rate_sanjae")
+    assert {r["@key"] for r in vat["rows"]} == {"rate_percent", "base"}
+    goyong = {
+        c["key"]: c for c in _rows(client, file="rates", table="variables/rate_goyong")["columns"]
+    }
+    assert (
+        goyong["rate_percent"]["label"] == "요율" and goyong["rate_percent"]["unit"] == "%"
+    )  # 파일 것이 이김
+    assert goyong["base"]["label"] == "밑수" and goyong["base"]["unit"] == ""
+
+
+def test_없는_파일_표는_404_경로_넘기도_404(client: TestClient) -> None:
+    for params in (
+        {"file": "nope", "table": "rows"},
+        {"file": "rates", "table": "nope"},
+        {"file": "../../config/config_db", "table": "rows"},
+        {"file": "002yr_01hr", "table": "features"},  # 강우 IDF 캐시 — 갈래표 밖
+        {"file": "_manifest", "table": "files"},
+    ):
+        assert client.get("/api/master-data/rows", params=params).status_code == 404, params