diff --git a/.beans/nuzlocke-tracker-i08l--implement-pinwheel-clause-support.md b/.beans/nuzlocke-tracker-i08l--implement-pinwheel-clause-support.md
new file mode 100644
index 0000000..afdff1d
--- /dev/null
+++ b/.beans/nuzlocke-tracker-i08l--implement-pinwheel-clause-support.md
@@ -0,0 +1,25 @@
+---
+# nuzlocke-tracker-i08l
+title: Implement Pinwheel Clause support
+status: completed
+type: feature
+priority: normal
+created_at: 2026-02-07T19:18:34Z
+updated_at: 2026-02-07T19:21:45Z
+---
+
+Add pinwheel_zone column to routes, pinwheelClause toggle to NuzlockeRules, zone-aware encounter locking on frontend and backend.
+
+## Checklist
+- [x] Alembic migration for pinwheel_zone column
+- [x] SQLAlchemy model update
+- [x] Pydantic schema updates
+- [x] Route list API helper update
+- [x] Encounter creation API zone-aware sibling check
+- [x] Seed loader update
+- [x] Seed data for Pinwheel Forest zones
+- [x] NuzlockeRules per-run toggle
+- [x] Frontend types (game.ts, admin.ts)
+- [x] Admin route form pinwheelZone input
+- [x] Encounter page zone-aware locking, counts, and filtering
+- [x] getZoneEncounters helper
\ No newline at end of file
diff --git a/backend/src/app/alembic/versions/a1b2c3d4e5f7_add_pinwheel_clause_support.py b/backend/src/app/alembic/versions/a1b2c3d4e5f7_add_pinwheel_clause_support.py
new file mode 100644
index 0000000..7fbbd92
--- /dev/null
+++ b/backend/src/app/alembic/versions/a1b2c3d4e5f7_add_pinwheel_clause_support.py
@@ -0,0 +1,29 @@
+"""add pinwheel clause support
+
+Revision ID: a1b2c3d4e5f7
+Revises: f6a7b8c9d0e1
+Create Date: 2026-02-07 12:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'a1b2c3d4e5f7'
+down_revision: Union[str, Sequence[str], None] = 'f6a7b8c9d0e1'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        'routes',
+        sa.Column('pinwheel_zone', sa.SmallInteger(), nullable=True),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column('routes', 'pinwheel_zone')
diff --git a/backend/src/app/api/encounters.py b/backend/src/app/api/encounters.py
index e40b9a5..dcedd1f 100644
--- a/backend/src/app/api/encounters.py
+++ b/backend/src/app/api/encounters.py
@@ -50,15 +50,30 @@ async def create_encounter(
             detail="Cannot create encounter on a parent route. Use a child route instead.",
         )
 
-    # If this route has a parent, check if any sibling already has an encounter
+    # If this route has a parent, check if sibling already has an encounter
     if route.parent_route_id is not None:
-        # Get all sibling route IDs (routes with same parent, including this one)
+        # Get all sibling routes (routes with same parent, including this one)
         siblings_result = await session.execute(
-            select(Route.id).where(Route.parent_route_id == route.parent_route_id)
+            select(Route).where(Route.parent_route_id == route.parent_route_id)
         )
-        sibling_ids = [r for r in siblings_result.scalars().all()]
+        siblings = siblings_result.scalars().all()
 
-        # Check if any sibling already has an encounter in this run
+        # Determine which siblings to check based on pinwheel clause
+        pinwheel_on = run.rules.get("pinwheelClause", True) if run.rules else True
+        any_has_zone = any(s.pinwheel_zone is not None for s in siblings)
+
+        if pinwheel_on and any_has_zone:
+            # Zone-aware: only check siblings in the same zone (null treated as 0)
+            my_zone = route.pinwheel_zone if route.pinwheel_zone is not None else 0
+            sibling_ids = [
+                s.id for s in siblings
+                if (s.pinwheel_zone if s.pinwheel_zone is not None else 0) == my_zone
+            ]
+        else:
+            # No pinwheel clause or no zones defined: all siblings share
+            sibling_ids = [s.id for s in siblings]
+
+        # Check if any relevant sibling already has an encounter in this run
         existing_encounter = await session.execute(
             select(Encounter)
             .where(
diff --git a/backend/src/app/api/games.py b/backend/src/app/api/games.py
index 8013d0e..126374b 100644
--- a/backend/src/app/api/games.py
+++ b/backend/src/app/api/games.py
@@ -80,6 +80,7 @@ async def list_game_routes(
             "game_id": route.game_id,
             "order": route.order,
             "parent_route_id": route.parent_route_id,
+            "pinwheel_zone": route.pinwheel_zone,
             "encounter_methods": methods,
         }
 
diff --git a/backend/src/app/models/route.py b/backend/src/app/models/route.py
index ccc7187..2d89a91 100644
--- a/backend/src/app/models/route.py
+++ b/backend/src/app/models/route.py
@@ -17,6 +17,7 @@ class Route(Base):
     parent_route_id: Mapped[int | None] = mapped_column(
         ForeignKey("routes.id", ondelete="CASCADE"), index=True, default=None
     )
+    pinwheel_zone: Mapped[int | None] = mapped_column(SmallInteger, default=None)
 
     game: Mapped["Game"] = relationship(back_populates="routes")
     route_encounters: Mapped[list["RouteEncounter"]] = relationship(
diff --git a/backend/src/app/schemas/game.py b/backend/src/app/schemas/game.py
index d3ef9cb..d903549 100644
--- a/backend/src/app/schemas/game.py
+++ b/backend/src/app/schemas/game.py
@@ -7,6 +7,7 @@ class RouteResponse(CamelModel):
     game_id: int
     order: int
     parent_route_id: int | None = None
+    pinwheel_zone: int | None = None
     encounter_methods: list[str] = []
 
 
@@ -56,12 +57,14 @@ class RouteCreate(CamelModel):
     name: str
     order: int
     parent_route_id: int | None = None
+    pinwheel_zone: int | None = None
 
 
 class RouteUpdate(CamelModel):
     name: str | None = None
     order: int | None = None
     parent_route_id: int | None = None
+    pinwheel_zone: int | None = None
 
 
 class RouteReorderItem(CamelModel):
diff --git a/backend/src/app/seeds/data/black-2.json b/backend/src/app/seeds/data/black-2.json
index ccb81d7..b00a9dc 100644
--- a/backend/src/app/seeds/data/black-2.json
+++ b/backend/src/app/seeds/data/black-2.json
@@ -1333,6 +1333,7 @@
       {
         "name": "Pinwheel Forest (Outside)",
         "order": 23,
+        "pinwheel_zone": 1,
         "encounters": [
           {
             "pokeapi_id": 533,
@@ -1379,6 +1380,7 @@
       {
         "name": "Pinwheel Forest (Inside)",
         "order": 24,
+        "pinwheel_zone": 2,
         "encounters": [
           {
             "pokeapi_id": 550,
diff --git a/backend/src/app/seeds/data/black.json b/backend/src/app/seeds/data/black.json
index 200ebef..0d75596 100644
--- a/backend/src/app/seeds/data/black.json
+++ b/backend/src/app/seeds/data/black.json
@@ -1321,6 +1321,7 @@
       {
         "name": "Pinwheel Forest (Outside)",
         "order": 25,
+        "pinwheel_zone": 1,
         "encounters": [
           {
             "pokeapi_id": 535,
@@ -1359,6 +1360,7 @@
       {
         "name": "Pinwheel Forest (Inside)",
         "order": 26,
+        "pinwheel_zone": 2,
         "encounters": [
           {
             "pokeapi_id": 550,
diff --git a/backend/src/app/seeds/data/white-2.json b/backend/src/app/seeds/data/white-2.json
index 027b942..30e252f 100644
--- a/backend/src/app/seeds/data/white-2.json
+++ b/backend/src/app/seeds/data/white-2.json
@@ -1333,6 +1333,7 @@
       {
         "name": "Pinwheel Forest (Outside)",
         "order": 23,
+        "pinwheel_zone": 1,
         "encounters": [
           {
             "pokeapi_id": 533,
@@ -1379,6 +1380,7 @@
       {
         "name": "Pinwheel Forest (Inside)",
         "order": 24,
+        "pinwheel_zone": 2,
         "encounters": [
           {
             "pokeapi_id": 10016,
diff --git a/backend/src/app/seeds/data/white.json b/backend/src/app/seeds/data/white.json
index 6eacfe8..60c4aae 100644
--- a/backend/src/app/seeds/data/white.json
+++ b/backend/src/app/seeds/data/white.json
@@ -1321,6 +1321,7 @@
       {
         "name": "Pinwheel Forest (Outside)",
         "order": 25,
+        "pinwheel_zone": 1,
         "encounters": [
           {
             "pokeapi_id": 535,
@@ -1359,6 +1360,7 @@
       {
         "name": "Pinwheel Forest (Inside)",
         "order": 26,
+        "pinwheel_zone": 2,
         "encounters": [
           {
             "pokeapi_id": 10016,
diff --git a/backend/src/app/seeds/loader.py b/backend/src/app/seeds/loader.py
index b575559..d44dbfe 100644
--- a/backend/src/app/seeds/loader.py
+++ b/backend/src/app/seeds/loader.py
@@ -109,9 +109,14 @@ async def upsert_routes(
                 game_id=game_id,
                 order=child["order"],
                 parent_route_id=parent_id,
+                pinwheel_zone=child.get("pinwheel_zone"),
             ).on_conflict_do_update(
                 constraint="uq_routes_game_name",
-                set_={"order": child["order"], "parent_route_id": parent_id},
+                set_={
+                    "order": child["order"],
+                    "parent_route_id": parent_id,
+                    "pinwheel_zone": child.get("pinwheel_zone"),
+                },
             )
             await session.execute(stmt)
 
diff --git a/frontend/src/components/admin/RouteFormModal.tsx b/frontend/src/components/admin/RouteFormModal.tsx
index f63ac42..14035af 100644
--- a/frontend/src/components/admin/RouteFormModal.tsx
+++ b/frontend/src/components/admin/RouteFormModal.tsx
@@ -13,10 +13,17 @@ interface RouteFormModalProps {
 export function RouteFormModal({ route, nextOrder, onSubmit, onClose, isSubmitting }: RouteFormModalProps) {
   const [name, setName] = useState(route?.name ?? '')
   const [order, setOrder] = useState(String(route?.order ?? nextOrder ?? 0))
+  const [pinwheelZone, setPinwheelZone] = useState(
+    route?.pinwheelZone != null ? String(route.pinwheelZone) : ''
+  )
 
   const handleSubmit = (e: FormEvent) => {
     e.preventDefault()
-    onSubmit({ name, order: Number(order) })
+    onSubmit({
+      name,
+      order: Number(order),
+      pinwheelZone: pinwheelZone !== '' ? Number(pinwheelZone) : null,
+    })
   }
 
   return (
@@ -47,6 +54,20 @@ export function RouteFormModal({ route, nextOrder, onSubmit, onClose, isSubmitti
           className="w-full px-3 py-2 border rounded-md dark:bg-gray-700 dark:border-gray-600"
         />
       </div>
+      <div>
+        <label className="block text-sm font-medium mb-1">Pinwheel Zone</label>
+        <input
+          type="number"
+          min={0}
+          value={pinwheelZone}
+          onChange={(e) => setPinwheelZone(e.target.value)}
+          placeholder="None"
+          className="w-full px-3 py-2 border rounded-md dark:bg-gray-700 dark:border-gray-600"
+        />
+        <p className="text-xs text-gray-500 dark:text-gray-400 mt-1">
+          Routes in the same zone share an encounter when the Pinwheel Clause is active
+        </p>
+      </div>
     </FormModal>
   )
 }
diff --git a/frontend/src/pages/RunEncounters.tsx b/frontend/src/pages/RunEncounters.tsx
index 9ea7950..b3fcadf 100644
--- a/frontend/src/pages/RunEncounters.tsx
+++ b/frontend/src/pages/RunEncounters.tsx
@@ -103,6 +103,40 @@ function getGroupEncounter(
   return null
 }
 
+/** Whether any child in this group has a pinwheelZone set. */
+function groupHasZones(group: RouteWithChildren): boolean {
+  return group.children.some((c) => c.pinwheelZone != null)
+}
+
+/** Get the effective zone for a route (null treated as 0). */
+function effectiveZone(route: Route): number {
+  return route.pinwheelZone ?? 0
+}
+
+/**
+ * Get encounters grouped by zone within a route group.
+ * Returns a Map from zone number to the encounter in that zone.
+ */
+function getZoneEncounters(
+  group: RouteWithChildren,
+  encounterByRoute: Map<number, EncounterDetail>,
+): Map<number, EncounterDetail> {
+  const zoneMap = new Map<number, EncounterDetail>()
+  for (const child of group.children) {
+    const enc = encounterByRoute.get(child.id)
+    if (enc) {
+      zoneMap.set(effectiveZone(child), enc)
+    }
+  }
+  return zoneMap
+}
+
+/** Count distinct zones in a group. */
+function countDistinctZones(group: RouteWithChildren): number {
+  const zones = new Set(group.children.map(effectiveZone))
+  return zones.size
+}
+
 interface RouteGroupProps {
   group: RouteWithChildren
   encounterByRoute: Map<number, EncounterDetail>
@@ -110,6 +144,7 @@ interface RouteGroupProps {
   onToggleExpand: () => void
   onRouteClick: (route: Route) => void
   filter: 'all' | RouteStatus
+  pinwheelClause: boolean
 }
 
 function RouteGroup({
@@ -119,14 +154,37 @@ function RouteGroup({
   onToggleExpand,
   onRouteClick,
   filter,
+  pinwheelClause,
 }: RouteGroupProps) {
   const groupEncounter = getGroupEncounter(group, encounterByRoute)
-  const groupStatus = groupEncounter ? groupEncounter.status : 'none'
+  const usePinwheel = pinwheelClause && groupHasZones(group)
+  const zoneEncounters = usePinwheel
+    ? getZoneEncounters(group, encounterByRoute)
+    : null
+
+  // For pinwheel groups, determine status from all zone statuses
+  let groupStatus: RouteStatus
+  if (usePinwheel && zoneEncounters && zoneEncounters.size > 0) {
+    // Use the first encounter's status as representative for the header
+    groupStatus = groupEncounter ? groupEncounter.status : 'none'
+  } else {
+    groupStatus = groupEncounter ? groupEncounter.status : 'none'
+  }
   const si = statusIndicator[groupStatus]
 
   // For groups, check if it matches the filter
-  if (filter !== 'all' && groupStatus !== filter) {
-    return null
+  if (filter !== 'all') {
+    if (usePinwheel) {
+      // Show group if any zone matches the filter
+      const anyChildMatches = group.children.some((child) => {
+        const enc = encounterByRoute.get(child.id)
+        return getRouteStatus(enc) === filter
+      })
+      // Also check children without encounters (for 'none' filter)
+      if (!anyChildMatches) return null
+    } else if (groupStatus !== filter) {
+      return null
+    }
   }
 
   const hasGroupEncounter = groupEncounter !== null
@@ -192,7 +250,16 @@ function RouteGroup({
             const childEncounter = encounterByRoute.get(child.id)
             const childStatus = getRouteStatus(childEncounter)
             const childSi = statusIndicator[childStatus]
-            const isDisabled = hasGroupEncounter && !childEncounter
+
+            let isDisabled: boolean
+            if (usePinwheel && zoneEncounters) {
+              // Zone-aware: only lock if this child's zone already has an encounter
+              const myZone = effectiveZone(child)
+              isDisabled = zoneEncounters.has(myZone) && !childEncounter
+            } else {
+              // Classic: whole group shares one encounter
+              isDisabled = hasGroupEncounter && !childEncounter
+            }
 
             return (
               <button
@@ -334,17 +401,32 @@ export function RunEncounters() {
     )
   }
 
-  // Count completed locations (groups count as 1, standalone routes count as 1)
-  const completedCount = organizedRoutes.filter((r) => {
-    if (r.children.length > 0) {
-      // It's a group - check if any child has an encounter
-      return getGroupEncounter(r, encounterByRoute) !== null
-    }
-    // Standalone route
-    return encounterByRoute.has(r.id)
-  }).length
+  const pinwheelClause = run.rules?.pinwheelClause ?? true
 
-  const totalLocations = organizedRoutes.length
+  // Count completed locations (zone-aware when pinwheel clause is on)
+  let completedCount = 0
+  let totalLocations = 0
+  for (const r of organizedRoutes) {
+    if (r.children.length > 0) {
+      const usePinwheel = pinwheelClause && groupHasZones(r)
+      if (usePinwheel) {
+        const distinctZones = countDistinctZones(r)
+        const zoneEncs = getZoneEncounters(r, encounterByRoute)
+        totalLocations += distinctZones
+        completedCount += zoneEncs.size
+      } else {
+        totalLocations += 1
+        if (getGroupEncounter(r, encounterByRoute) !== null) {
+          completedCount += 1
+        }
+      }
+    } else {
+      totalLocations += 1
+      if (encounterByRoute.has(r.id)) {
+        completedCount += 1
+      }
+    }
+  }
 
   const isActive = run.status === 'active'
   const alive = run.encounters.filter(
@@ -413,7 +495,15 @@ export function RunEncounters() {
     if (filter === 'all') return true
 
     if (r.children.length > 0) {
-      // It's a group
+      const usePinwheel = pinwheelClause && groupHasZones(r)
+      if (usePinwheel) {
+        // Show group if any child/zone matches the filter
+        return r.children.some((child) => {
+          const enc = encounterByRoute.get(child.id)
+          return getRouteStatus(enc) === filter
+        })
+      }
+      // Classic: single status for whole group
       const groupEnc = getGroupEncounter(r, encounterByRoute)
       return getRouteStatus(groupEnc ?? undefined) === filter
     }
@@ -665,6 +755,7 @@ export function RunEncounters() {
                 onToggleExpand={() => toggleGroup(route.id)}
                 onRouteClick={handleRouteClick}
                 filter={filter}
+                pinwheelClause={pinwheelClause}
               />
             )
           }
diff --git a/frontend/src/types/admin.ts b/frontend/src/types/admin.ts
index 21be737..0c51032 100644
--- a/frontend/src/types/admin.ts
+++ b/frontend/src/types/admin.ts
@@ -19,11 +19,13 @@ export interface UpdateGameInput {
 export interface CreateRouteInput {
   name: string
   order: number
+  pinwheelZone?: number | null
 }
 
 export interface UpdateRouteInput {
   name?: string
   order?: number
+  pinwheelZone?: number | null
 }
 
 export interface RouteReorderItem {
diff --git a/frontend/src/types/game.ts b/frontend/src/types/game.ts
index cc7f1e0..b38a81d 100644
--- a/frontend/src/types/game.ts
+++ b/frontend/src/types/game.ts
@@ -15,6 +15,7 @@ export interface Route {
   gameId: number
   order: number
   parentRouteId: number | null
+  pinwheelZone: number | null
   encounterMethods: string[]
 }
 
diff --git a/frontend/src/types/rules.ts b/frontend/src/types/rules.ts
index ab6337c..ebfe365 100644
--- a/frontend/src/types/rules.ts
+++ b/frontend/src/types/rules.ts
@@ -5,6 +5,7 @@ export interface NuzlockeRules {
   nicknameRequired: boolean
   duplicatesClause: boolean
   shinyClause: boolean
+  pinwheelClause: boolean
 
   // Difficulty modifiers
   hardcoreMode: boolean
@@ -19,6 +20,7 @@ export const DEFAULT_RULES: NuzlockeRules = {
   nicknameRequired: true,
   duplicatesClause: true,
   shinyClause: true,
+  pinwheelClause: true,
 
   // Difficulty modifiers - off by default
   hardcoreMode: false,
@@ -70,6 +72,13 @@ export const RULE_DEFINITIONS: RuleDefinition[] = [
       'Shiny Pokémon may always be caught, regardless of whether they are your first encounter.',
     category: 'core',
   },
+  {
+    key: 'pinwheelClause',
+    name: 'Pinwheel Clause',
+    description:
+      'Sub-zones within a location group each get their own encounter instead of sharing one.',
+    category: 'core',
+  },
 
   // Difficulty modifiers
   {