diff --git a/app/game-engine/package.json b/app/game-engine/package.json
index 7dc04d5..f45acb5 100644
--- a/app/game-engine/package.json
+++ b/app/game-engine/package.json
@@ -9,6 +9,9 @@
         "lint": "node -e \"console.log('lint not configured')\"",
         "test": "vitest run --config vitest.config.ts"
     },
+    "dependencies": {
+        "@sammo-ts/common": "workspace:*"
+    },
     "devDependencies": {
         "vitest": "^4.0.16"
     }
diff --git a/app/game-engine/src/lifecycle/clock.ts b/app/game-engine/src/lifecycle/clock.ts
index ce2c6b1..e29f259 100644
--- a/app/game-engine/src/lifecycle/clock.ts
+++ b/app/game-engine/src/lifecycle/clock.ts
@@ -1,76 +1 @@
-import type { Clock } from './types.js';
-
-export class SystemClock implements Clock {
-    // 시스템 시간을 기준으로 동작하는 기본 시계.
-    nowMs(): number {
-        return Date.now();
-    }
-
-    async sleepMs(ms: number): Promise<void> {
-        if (ms <= 0) {
-            return;
-        }
-        await new Promise((resolve) => setTimeout(resolve, ms));
-    }
-}
-
-export class ManualClock implements Clock {
-    // 테스트에서 시간을 직접 이동시키는 수동 시계.
-    private currentMs: number;
-
-    constructor(initialMs = 0) {
-        this.currentMs = initialMs;
-    }
-
-    nowMs(): number {
-        return this.currentMs;
-    }
-
-    async sleepMs(ms: number): Promise<void> {
-        if (ms <= 0) {
-            return;
-        }
-        this.currentMs += ms;
-    }
-
-    advanceMs(ms: number): void {
-        if (ms <= 0) {
-            return;
-        }
-        this.currentMs += ms;
-    }
-
-    setMs(ms: number): void {
-        this.currentMs = ms;
-    }
-}
-
-export class StepClock implements Clock {
-    // 호출마다 일정 간격씩 시간이 진행되는 시계.
-    private currentMs: number;
-    private readonly stepMs: number;
-
-    constructor(stepMs: number, initialMs = 0) {
-        if (stepMs <= 0) {
-            throw new Error('stepMs must be positive');
-        }
-        this.stepMs = stepMs;
-        this.currentMs = initialMs;
-    }
-
-    nowMs(): number {
-        this.currentMs += this.stepMs;
-        return this.currentMs;
-    }
-
-    async sleepMs(ms: number): Promise<void> {
-        if (ms <= 0) {
-            return;
-        }
-        this.currentMs += ms;
-    }
-
-    setMs(ms: number): void {
-        this.currentMs = ms;
-    }
-}
+export { ManualClock, StepClock, SystemClock } from '@sammo-ts/common';
diff --git a/app/game-engine/src/lifecycle/types.ts b/app/game-engine/src/lifecycle/types.ts
index 1f6b91c..b564d88 100644
--- a/app/game-engine/src/lifecycle/types.ts
+++ b/app/game-engine/src/lifecycle/types.ts
@@ -43,10 +43,7 @@ export type TurnDaemonCommand =
     | { type: 'resume'; reason?: string }
     | { type: 'shutdown'; reason?: string };
 
-export interface Clock {
-    nowMs(): number;
-    sleepMs(ms: number): Promise<void>;
-}
+export type { Clock } from '@sammo-ts/common';
 
 export interface TurnSchedule {
     getNextTurnTime(lastTurnTime: Date): Date;
diff --git a/packages/common/package.json b/packages/common/package.json
index c3f65ec..72cae07 100644
--- a/packages/common/package.json
+++ b/packages/common/package.json
@@ -9,10 +9,12 @@
         "build": "tsc -p tsconfig.json",
         "dev": "node -e \"console.log('dev not configured')\"",
         "lint": "node -e \"console.log('lint not configured')\"",
-        "test": "node -e \"console.log('test not configured')\""
+        "test": "vitest run --config vitest.config.ts"
     },
     "dependencies": {
         "js-sha512": "^0.9.0"
     },
-    "devDependencies": {}
+    "devDependencies": {
+        "vitest": "^4.0.16"
+    }
 }
diff --git a/packages/common/src/index.ts b/packages/common/src/index.ts
index 4b4a672..bd23b9e 100644
--- a/packages/common/src/index.ts
+++ b/packages/common/src/index.ts
@@ -1,4 +1,5 @@
 export * from './rng.js';
+export * from './time/Clock.js';
 export * from './util/BytesLike.js';
 export * from './util/convertBytesLikeToArrayBuffer.js';
 export * from './util/convertBytesLikeToUint8Array.js';
diff --git a/packages/common/src/time/Clock.ts b/packages/common/src/time/Clock.ts
new file mode 100644
index 0000000..d285bab
--- /dev/null
+++ b/packages/common/src/time/Clock.ts
@@ -0,0 +1,86 @@
+export interface Clock {
+    nowMs(): number;
+    sleepMs(ms: number): Promise<void>;
+}
+
+export class SystemClock implements Clock {
+    // 시스템 시간을 기준으로 동작하는 기본 시계.
+    nowMs(): number {
+        return Date.now();
+    }
+
+    async sleepMs(ms: number): Promise<void> {
+        if (ms <= 0) {
+            return;
+        }
+        await new Promise((resolve) => setTimeout(resolve, ms));
+    }
+}
+
+export class ManualClock implements Clock {
+    // 테스트에서 시간을 직접 이동시키는 수동 시계.
+    private currentMs: number;
+
+    constructor(initialMs = 0) {
+        this.currentMs = initialMs;
+    }
+
+    nowMs(): number {
+        return this.currentMs;
+    }
+
+    async sleepMs(ms: number): Promise<void> {
+        if (ms <= 0) {
+            return;
+        }
+        this.currentMs += ms;
+    }
+
+    advanceMs(ms: number): void {
+        if (ms <= 0) {
+            return;
+        }
+        this.currentMs += ms;
+    }
+
+    setMs(ms: number): void {
+        this.currentMs = ms;
+    }
+}
+
+export class StepClock implements Clock {
+    // 호출마다 일정 간격씩 시간이 진행되는 시계.
+    private currentMs: number;
+    private readonly stepMs: number;
+
+    constructor(stepMs: number, initialMs = 0) {
+        if (stepMs <= 0) {
+            throw new Error('stepMs must be positive');
+        }
+        this.stepMs = stepMs;
+        this.currentMs = initialMs;
+    }
+
+    nowMs(): number {
+        this.currentMs += this.stepMs;
+        return this.currentMs;
+    }
+
+    async sleepMs(ms: number): Promise<void> {
+        if (ms <= 0) {
+            return;
+        }
+        this.currentMs += ms;
+    }
+
+    advanceMs(ms: number): void {
+        if (ms <= 0) {
+            return;
+        }
+        this.currentMs += ms;
+    }
+
+    setMs(ms: number): void {
+        this.currentMs = ms;
+    }
+}
diff --git a/app/game-engine/test/clock.test.ts b/packages/common/test/clock.test.ts
similarity index 85%
rename from app/game-engine/test/clock.test.ts
rename to packages/common/test/clock.test.ts
index 0df36ec..7a7a8c5 100644
--- a/app/game-engine/test/clock.test.ts
+++ b/packages/common/test/clock.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, it } from 'vitest';
-import { ManualClock, StepClock } from '../src/lifecycle/clock.js';
+
+import { ManualClock, StepClock } from '../src/time/Clock.js';
 
 describe('ManualClock', () => {
     it('returns current time without advancing', () => {
@@ -37,6 +38,12 @@ describe('StepClock', () => {
         expect(clock.nowMs()).toBe(1250);
     });
 
+    it('advances manually', () => {
+        const clock = new StepClock(10, 0);
+        clock.advanceMs(50);
+        expect(clock.nowMs()).toBe(60);
+    });
+
     it('rejects non-positive step', () => {
         expect(() => new StepClock(0)).toThrow('stepMs must be positive');
         expect(() => new StepClock(-5)).toThrow('stepMs must be positive');
diff --git a/packages/common/vitest.config.ts b/packages/common/vitest.config.ts
new file mode 100644
index 0000000..5c63f1e
--- /dev/null
+++ b/packages/common/vitest.config.ts
@@ -0,0 +1,9 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+    test: {
+        environment: 'node',
+        globals: true,
+        include: ['test/**/*.test.ts'],
+    },
+});
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index e3d322a..d912c28 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -18,6 +18,10 @@ importers:
   app/game-api: {}
 
   app/game-engine:
+    dependencies:
+      '@sammo-ts/common':
+        specifier: workspace:*
+        version: link:../../packages/common
     devDependencies:
       vitest:
         specifier: ^4.0.16
@@ -34,6 +38,10 @@ importers:
       js-sha512:
         specifier: ^0.9.0
         version: 0.9.0
+    devDependencies:
+      vitest:
+        specifier: ^4.0.16
+        version: 4.0.16(@types/node@20.19.27)
 
   packages/infra:
     dependencies: