diff --git a/A00_Common/design/design_pipe_ids.ts b/A00_Common/design/design_pipe_ids.ts
index d5c9ef567..02c93b7b6 100644
--- a/A00_Common/design/design_pipe_ids.ts
+++ b/A00_Common/design/design_pipe_ids.ts
@@ -46,6 +46,20 @@ export function pipeIdAt(chainageM: number, projectId: string | null = active):
   return id;
 }
 
+/** 그 자리 관의 id — 장부에 있을 때만(안 지음 · 411-E). */
+export function pipeIdNear(chainageM: number, projectId: string | null = active): string | null {
+  if (!projectId) return null;
+  return nearestWithin(bookOf(projectId).ids, chainageM, (entry) => entry.at)?.id ?? null;
+}
+
+/** 지금 관 자리(`keep`) 근처에 없는 기록을 뺌 — 옮긴 사이 옛 측점이 지은 헛 id 정리(411-E). */
+export function prunePipeIds(keep: ReadonlyArray<number>, projectId: string | null = active): void {
+  if (!projectId || !keep.length) return; // 빈 목록 = 아직 못 받음 · 다 지움 — 장부 그대로
+  const book = bookOf(projectId);
+  const ids = book.ids.filter((entry) => keep.some((at) => isNear(entry.at, at)));
+  if (ids.length !== book.ids.length) writeState("pipe-ids", { next: book.next, ids }, projectId);
+}
+
 /** id 의 관 자리 — 장부 · 옛 자리 이름 순 · 관 id 가 아니면 null. */
 export function pipeChainageOf(id: string, projectId: string | null = active): number | null {
   if (!id.startsWith("pipe-")) return null;
diff --git a/A00_Common/design/design_view_profile.ts b/A00_Common/design/design_view_profile.ts
index 2ee2a5f5f..9799e068c 100644
--- a/A00_Common/design/design_view_profile.ts
+++ b/A00_Common/design/design_view_profile.ts
@@ -66,7 +66,7 @@ import "../../B05_Profile/B05_Profile_UI_Style.css";
 import "../../B05_Profile/B05_Profile_UI_Style_Table.css";
 import "../../B05_Profile/B05_Profile_UI_Style_Drainage.css";
 import "../../B05_Profile/B05_Profile_UI_Style_Structures.css";
-import { pipeIdAt, placePipeIds } from "./design_pipe_ids";
+import { pipeIdAt, placePipeIds, prunePipeIds } from "./design_pipe_ids";
 import { useDesignStore } from "./design_store";
 import { setPlusStations } from "../../common_util/common_util_structure_station";
 import {
@@ -132,6 +132,10 @@ export async function mountProfileView(
         pipe.id ? [[pipe.id, pipeIdAt(pipe.chainage_m, activeProjectId)] as const] : [],
       ),
     );
+    prunePipeIds(
+      shown.map((pipe) => pipe.chainage_m),
+      activeProjectId,
+    ); // 헛 id 정리(411-E)
     return shown;
   };
   const applyPipes = (reported: PipeReport, carryEdits = true): void => {
diff --git a/B06_Section/B06_Section_Station_Keys.ts b/B06_Section/B06_Section_Station_Keys.ts
index f28f8f3e3..3677b57e7 100644
--- a/B06_Section/B06_Section_Station_Keys.ts
+++ b/B06_Section/B06_Section_Station_Keys.ts
@@ -16,7 +16,7 @@
  * ========================================================================== */
 
 import { readState, writeState } from "../A00_Common/b_page_state";
-import { pipeIdAt } from "../A00_Common/design/design_pipe_ids";
+import { pipeIdAt, pipeIdNear } from "../A00_Common/design/design_pipe_ids";
 import { showToast } from "@ui/ui_template_elements";
 import {
   chainageKey,
@@ -116,15 +116,18 @@ export function stationKeysOf(
   intervalM: number | null,
 ): Keyed[] {
   const known = projectId ? (owners.get(projectId) ?? []) : [];
+  const planned = known.some((owner) => owner.kind === "pipe");
   const keys = sections.map((section) => {
     const at = section.chainage_m;
     let key: string;
     if (section.kind === "irregular") {
       const owner = known.find((entry) => Math.abs(entry.at - at) < NEAR_M);
       if (owner) key = stationKey("irregular", at, intervalM, owner.id, owner.kind, owner.role);
-      else if (looksLikePipe(section))
-        key = stationKey("pipe", at, intervalM, pipeIdAt(at, projectId));
-      else
+      else if (looksLikePipe(section)) {
+        // 관 계획을 아는 동안(초안) 계획에 없는 관 측점 = 옮겨 간 옛 자리 — 세션 id 를 새로 안 지음(411-E)
+        const id = planned ? pipeIdNear(at, projectId) : pipeIdAt(at, projectId);
+        key = id ? stationKey("pipe", at, intervalM, id) : stationKey("irregular", at, intervalM);
+      } else
         key = section.grid
           ? stationKey("regular", at, intervalM)
           : stationKey("irregular", at, intervalM);
diff --git a/resources/tester/helper_411_b_entry.ts b/resources/tester/helper_411_b_entry.ts
index 4023287b6..0e45be03d 100644
--- a/resources/tester/helper_411_b_entry.ts
+++ b/resources/tester/helper_411_b_entry.ts
@@ -5,7 +5,9 @@ export { followPipeReports } from "../../B05_Profile/logic/B05_Profile_Pipeline_
 export { followedMarks } from "../../B05_Profile/logic/B05_Profile_Structure_Follow";
 export {
   movePipeId,
+  pipeIdNear,
   placePipeIds,
+  prunePipeIds,
   pipeChainageOf,
   pipeIdAt,
   usePipeIds,
diff --git a/resources/tester/helper_411_b_pipe_id_pairing.mjs b/resources/tester/helper_411_b_pipe_id_pairing.mjs
index 0af5598f8..c41f8f15d 100644
--- a/resources/tester/helper_411_b_pipe_id_pairing.mjs
+++ b/resources/tester/helper_411_b_pipe_id_pairing.mjs
@@ -161,4 +161,23 @@ m.useStationOwners(P, planned);
 out.keysNoPipes = m.stationKeysOf(P, sections, 20).map((k) => k.key);
 out.pipelineKey = m.pipelineStationKey("pipe", "p8017");
 
+/* 7. 411-E — 관 계획을 아는 동안 옛 자리 관 측점(옮겨 간 자리)은 세션 id 를 안 지음 · 헛 id 정리 */
+const E = "e411";
+m.usePipeIds(E);
+const e1 = m.pipeIdAt(80, E); // 옮긴 관(새 자리)
+const bookSize = () => JSON.parse(sessionStorage.getItem(`aislo:draft:pipe-ids:${E}`)).ids.length;
+m.useStationOwners(E, [{ chainage_m: 80, owners: ["p15000"], role: "anchor" }], [{ id: "p15000" }]);
+const staleSections = [
+  { chainage_m: 80, kind: "irregular", structure: "파형강관 D800", culvert: {} },
+  { chainage_m: 150, kind: "irregular", structure: "파형강관 D800", culvert: {} }, // 옛 자리
+];
+out.staleKeys = m.stationKeysOf(E, staleSections, 20).map((k) => k.key);
+out.staleBook = bookSize();
+m.useStationOwners(E, []); // 관 계획 모름(초안 없음) = 옛 갈래 그대로 지음
+out.legacyKey = m.stationKeysOf(E, [staleSections[1]], 20)[0].key;
+out.legacyBook = bookSize();
+m.prunePipeIds([80], E); // 지금 관 자리만 남김
+out.pruned = { size: bookSize(), at80: m.pipeIdAt(80, E), e1 };
+m.usePipeIds(P);
+
 process.stdout.write(JSON.stringify(out));
diff --git a/resources/tester/test_411_b_pipe_id_pairing.py b/resources/tester/test_411_b_pipe_id_pairing.py
index 2e0a47b5e..f469b95a2 100644
--- a/resources/tester/test_411_b_pipe_id_pairing.py
+++ b/resources/tester/test_411_b_pipe_id_pairing.py
@@ -113,3 +113,13 @@ def test_B06_열쇠는_서버_관_id_도_pipe(out):
     assert out["keys"] == ["structure:st-1", "pipe:p8017"]
     assert out["keys"][1] == out["pipelineKey"]  # 계산 묶음 측점 열쇠와 같음
     assert out["keysNoPipes"][1] == "structure:p8017"  # 관 목록을 안 주면 옛 갈래(대조)
+
+
+def test_411_E_옛_자리_관_측점은_헛_id_안_지음(out):
+    assert out["staleKeys"] == ["pipe:p15000", "at:150.00"]
+    assert out["staleBook"] == 1  # 세션 id 표에 헛 id 0
+    assert out["legacyKey"] == "pipe:pipe-s2" and out["legacyBook"] == 2  # 초안 없음 = 옛 갈래
+
+
+def test_411_E_헛_id_정리(out):
+    assert out["pruned"] == {"size": 1, "at80": out["pruned"]["e1"], "e1": "pipe-s1"}