diff --git a/src/core/Board.ts b/src/core/Board.ts
index cdb17c6..0e383c1 100644
--- a/src/core/Board.ts
+++ b/src/core/Board.ts
@@ -35,9 +35,9 @@ export class Board {
     for (let index = 0; index < this.totalPitCount(); index++) {
       const pitType = this.getPitTypeByIndex(index);
       if (pitType === 'player1Pit' || pitType === 'player2Pit') {
-        pitArray[index] = new Pit(initialStoneCountInPits);
+        pitArray[index] = new Pit(index, initialStoneCountInPits);
       } else if (pitType === 'player1Bank' || pitType === 'player2Bank') {
-        pitArray[index] = new Bank(0);
+        pitArray[index] = new Bank(index, 0);
       }
     }
     return pitArray;
diff --git a/src/core/Pit.ts b/src/core/Pit.ts
index 5081e1b..a95aa68 100644
--- a/src/core/Pit.ts
+++ b/src/core/Pit.ts
@@ -1,7 +1,9 @@
 export class Pit {
+  index: number;
   stoneCount: number;
 
-  constructor(stoneCount = 0) {
+  constructor(index: number, stoneCount = 0) {
+    this.index = index;
     this.stoneCount = stoneCount;
   }
 
@@ -19,8 +21,8 @@ export class Pit {
 }
 
 export class Bank extends Pit {
-  constructor(stoneCount = 0) {
-    super(stoneCount);
+  constructor(index: number, stoneCount = 0) {
+    super(index, stoneCount);
   }
 
   override get isBank(): boolean {
diff --git a/tests/Board.test.ts b/tests/Board.test.ts
index f2e8df0..85ca668 100644
--- a/tests/Board.test.ts
+++ b/tests/Board.test.ts
@@ -1,6 +1,23 @@
 import { Board } from '../src/core/Board';
 
 describe('Board Test', () => {
+  test('test pit index', () => {
+    const board = new Board(6, 4);
+    expect(board.pits[0].index).toBe(0);
+    expect(board.pits[1].index).toBe(1);
+    expect(board.pits[2].index).toBe(2);
+    expect(board.pits[3].index).toBe(3);
+    expect(board.pits[4].index).toBe(4);
+    expect(board.pits[5].index).toBe(5);
+    expect(board.pits[6].index).toBe(6);
+    expect(board.pits[7].index).toBe(7);
+    expect(board.pits[8].index).toBe(8);
+    expect(board.pits[9].index).toBe(9);
+    expect(board.pits[10].index).toBe(10);
+    expect(board.pits[11].index).toBe(11);
+    expect(board.pits[12].index).toBe(12);
+    expect(board.pits[13].index).toBe(13);
+  });
   test('test getPitTypeByIndex', () => {
     const board = new Board(6, 4);
     expect(board.getPitTypeByIndex(0)).toBe('player1Pit');