diff --git a/src/core/abut/edit.ts b/src/core/abut/edit.ts
index d859be6..f8e0186 100644
--- a/src/core/abut/edit.ts
+++ b/src/core/abut/edit.ts
@@ -13,6 +13,7 @@ import { resolveWallRebar, wallRebarIssues, type AbutWallRebarSettings } from '.
 import { parapetRebarIssues, resolveParapetRebar, type AbutParapetRebarSettings } from './rebar/parapet';
 import { resolveWingRebar, wingRebarIssues, type AbutWingRebarSettings } from './rebar/wing';
 import { resolveSlabRebar, slabRebarIssues, type AbutSlabRebarSettings } from './rebar/slab';
+import { blockRebarIssues, resolveBlockRebar, type AbutBlockSettings } from './rebar/block';
 import { abutBearingRuleIssues, resolveBearingRule, type AbutBearingRule } from './bearing-table';
 
 export type AbutEditKey = 'seatEl' | 'foundationBottomEl' | 'groundEl' | 'pileLengthMm' | 'skewDeg' | 'slopeI';
@@ -222,6 +223,16 @@ export function applySlabRebar(rec: AbutRecord, patch: Partial<AbutSlabRebarSett
   return { ...rec, rebar: { ...(rec.rebar ?? {}), slab } };
 }
 
+/** Changes ③ 받침블럭 배근 values (only the changed ones are kept; undefined clears one), refused with a Korean message. */
+export function applyBlockRebar(rec: AbutRecord, patch: Partial<AbutBlockSettings>): AbutRecord {
+  for (const v of Object.values(patch)) if (typeof v === 'number' && !Number.isFinite(v)) throw new Error('숫자를 입력하세요.');
+  const block: Partial<AbutBlockSettings> = { ...(rec.rebar?.block ?? {}), ...patch };
+  for (const key of Object.keys(block) as (keyof AbutBlockSettings)[]) if (block[key] === undefined) delete block[key];
+  const issues = blockRebarIssues(resolveBlockRebar(block));
+  if (issues.length > 0) throw new Error(issues[0]);
+  return { ...rec, rebar: { ...(rec.rebar ?? {}), block } };
+}
+
 /** Changes one 접속슬래브 dim, refused with a Korean message when the slab would not build. */
 export function applySlabEdit(rec: AbutRecord, key: (typeof SLAB_EDIT_FIELDS)[number]['key'], value: number): AbutRecord {
   if (!Number.isFinite(value)) throw new Error('숫자를 입력하세요.');
diff --git a/src/core/abut/parse.ts b/src/core/abut/parse.ts
index 7cd38d3..25dcd95 100644
--- a/src/core/abut/parse.ts
+++ b/src/core/abut/parse.ts
@@ -20,6 +20,7 @@ import type { AbutWallRebarSettings } from './rebar/wall';
 import type { AbutParapetRebarSettings } from './rebar/parapet';
 import type { AbutWingRebarSettings } from './rebar/wing';
 import type { AbutSlabRebarSettings } from './rebar/slab';
+import type { AbutBlockSettings } from './rebar/block';
 
 type Cell = string | number | null | undefined;
 type Grid = Cell[][];
@@ -71,7 +72,7 @@ export interface AbutRecord {
   /** 지반·지층 입력 (② 지반·지층 카드, 교각과 같은 필드). Absent = 육상, 지하수위 없음, 지층 행 없음. */
   ground?: AbutGround;
   /** ③ 배근 입력 (부재별, 바꾼 값만). Absent = 엑셀 Abut 시트 기본값. */
-  rebar?: { footing?: Partial<AbutFootingRebarSettings>; wall?: Partial<AbutWallRebarSettings>; parapet?: Partial<AbutParapetRebarSettings>; wing?: Partial<AbutWingRebarSettings>; slab?: Partial<AbutSlabRebarSettings> };
+  rebar?: { footing?: Partial<AbutFootingRebarSettings>; wall?: Partial<AbutWallRebarSettings>; parapet?: Partial<AbutParapetRebarSettings>; wing?: Partial<AbutWingRebarSettings>; slab?: Partial<AbutSlabRebarSettings>; block?: Partial<AbutBlockSettings> };
   /** 예전 "좌우 같게" 값 (2026-11-04 이전 파일). 지금은 읽기만 하고 쓰지 않는다. */
   wingsLinked?: boolean;
 }
diff --git a/src/core/project.ts b/src/core/project.ts
index 1d6fb31..d974b8e 100644
--- a/src/core/project.ts
+++ b/src/core/project.ts
@@ -180,6 +180,9 @@ export function checkStoredAbutments(list: unknown): void {
       for (const [key, v] of Object.entries(a.rebar.slab ?? {})) {
         if (!finite(v)) throw new Error(`${who}: 접속슬래브 배근 값 ${key}이(가) 맞지 않습니다.`);
       }
+      for (const [key, v] of Object.entries(a.rebar.block ?? {})) {
+        if (!finite(v)) throw new Error(`${who}: 받침블럭 배근 값 ${key}이(가) 맞지 않습니다.`);
+      }
     }
     if (a.wingsLinked !== undefined && typeof a.wingsLinked !== 'boolean') throw new Error(`${who}: 좌우 같게 값이 맞지 않습니다.`);
     if (a.wings !== undefined) {
diff --git a/tests/abut-rebar-block.test.ts b/tests/abut-rebar-block.test.ts
index 3eebb0d..fe0f763 100644
--- a/tests/abut-rebar-block.test.ts
+++ b/tests/abut-rebar-block.test.ts
@@ -50,3 +50,25 @@ describe('교대 받침블럭 배근 A1 (AD6, 교대 기획서 §10)', () => {
     expect(len).toBeCloseTo(1100, 6);
   });
 });
+
+import { applyBlockRebar } from '../src/core/abut/edit';
+import { checkStoredAbutments } from '../src/core/project';
+import { parseAbutments } from '../src/core/abut/parse';
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import * as XLSX from 'xlsx';
+
+describe('③ 받침블럭 배근 입력 저장', () => {
+  const rec = parseAbutments(XLSX.read(readFileSync(fileURLToPath(new URL('../../../RAG/운곡교P1입력.xlsx', import.meta.url))), { type: 'buffer' })).abutments[0];
+  it('stores only the changed values; undefined links back; refuses bad values', () => {
+    const a = applyBlockRebar(rec, { spacingS1: 150, legLength: 800 });
+    expect(a.rebar?.block).toEqual({ spacingS1: 150, legLength: 800 });
+    expect(applyBlockRebar(a, { spacingS1: undefined }).rebar?.block).toEqual({ legLength: 800 });
+    expect(() => applyBlockRebar(rec, { legLength: 0 })).toThrow();
+  });
+
+  it('the project file keeps the 받침블럭 input and refuses a non-number', () => {
+    expect(() => checkStoredAbutments([applyBlockRebar(rec, { coverTop: 60 })])).not.toThrow();
+    expect(() => checkStoredAbutments([{ ...rec, rebar: { block: { coverTop: 'x' } } as never }])).toThrow('받침블럭 배근');
+  });
+});