diff --git a/cjsmin/src/chess.ts b/cjsmin/src/chess.ts
index c19e8c1..a4e585e 100644
--- a/cjsmin/src/chess.ts
+++ b/cjsmin/src/chess.ts
@@ -53,6 +53,26 @@ export type PrettyMove = {
   uas: UASymbol;
 };
 
+export type PromotablePiece = 'q' | 'r' | 'b' | 'n';
+
+export type Pawns =
+  | 'pa'
+  | 'pb'
+  | 'pc'
+  | 'pd'
+  | 'pe'
+  | 'pf'
+  | 'pg'
+  | 'ph'
+  | 'PA'
+  | 'PB'
+  | 'PC'
+  | 'PD'
+  | 'PE'
+  | 'PF'
+  | 'PG'
+  | 'PH';
+
 export type UASymbol =
   | 'RA'
   | 'NB'
diff --git a/src/metrics/moves.ts b/src/metrics/moves.ts
index 3177c04..6059f1f 100644
--- a/src/metrics/moves.ts
+++ b/src/metrics/moves.ts
@@ -1,5 +1,6 @@
 import { Chess } from '../../cjsmin/src/chess';
 import { FileReaderGame } from '../types';
+
 export async function getGameWithMostMoves(games: FileReaderGame[]) {
   console.time('Task 5: getGameWithMostMoves');
   let maxNumMoves = 0;
diff --git a/src/metrics/promotions.ts b/src/metrics/promotions.ts
index 73fec04..ccb8fd4 100644
--- a/src/metrics/promotions.ts
+++ b/src/metrics/promotions.ts
@@ -1,54 +1,57 @@
-import { Chess } from '../../cjsmin/src/chess';
-import { FileReaderGame } from '../types';
-
-export async function getPiecePromotionInfo(games: FileReaderGame[]) {
-  console.time('Task 7: getPiecePromotionInfo');
-  let ambigPiecePromotedToMap = {};
-  let promotingPieceMap = {};
-
-  for (const game of games) {
-    const chess = new Chess();
-    chess.loadPgn(game.moves);
-    const chessHistory = chess.history();
+import {
+  Pawns,
+  Piece,
+  PrettyMove,
+  PromotablePiece,
+} from '../../cjsmin/src/chess';
+import { Metric } from './metric';
+
+export class PromotionMetric implements Metric {
+  //uas pawns mapped to count of promotions to each piece type
+  //prettier-ignore
+  promotionMap: {
+    [key in Pawns]: {
+      [key in PromotablePiece]: number;
+      }
+  };
 
-    for (const moveInfo of chessHistory) {
-      if (moveInfo.originalString.includes('=')) {
-        // REGEX to only capture the piece type
-        const piecePromotedTo = moveInfo.originalString
-          .split('=')[1]
-          .match(/[a-zA-Z]/)[0];
+  constructor() {
+    this.clear();
+  }
 
-        const promotingPiece = moveInfo.uas;
+  clear(): void {
+    let promotionMap = {};
+    //prettier-ignore
+    for (const pawn of ["pa", "pb", "pc", "pd", "pe", "pf", "pg", "ph", 'PA', 'PB', 'PC', 'PD', 'PE', 'PF', 'PG', 'PH']) {
+      promotionMap[pawn] = { q: 0, r: 0, b: 0, n: 0 };
+    }
+    this.promotionMap = promotionMap as any;
+  }
 
+  processGame(game: { move: PrettyMove; board: Piece[] }[], gameLink?: string) {
+    for (const { move } of game) {
+      // TODO: we can use flags instead of includes('=)
+      if (move.originalString.includes('=')) {
         // update ambigPiecePromotedToMap
-        if (!ambigPiecePromotedToMap[piecePromotedTo]) {
-          ambigPiecePromotedToMap[piecePromotedTo] = 0;
-        }
-        ambigPiecePromotedToMap[piecePromotedTo]++;
-
-        // update promotingPieceMap
-        if (!promotingPieceMap[promotingPiece]) {
-          promotingPieceMap[promotingPiece] = 0;
-        }
-        promotingPieceMap[promotingPiece]++;
+        this.promotionMap[move.uas][move.promotion]++;
       }
     }
   }
 
-  // promotions facts
-  console.log('PROMOTIONS FACTS:');
-  console.log(
-    'How often a piece is promoted to different ambiguous piece types:'
-  ),
-    console.table(ambigPiecePromotedToMap);
-  console.log('How often unambiguous piece is promoted:'),
-    console.table(promotingPieceMap);
-  console.log('==============================================================');
-  console.log('\n');
-
-  console.timeEnd('Task 7: getPiecePromotionInfo');
-  return {
-    ambigPiecePromotedToMap,
-    promotingPieceMap,
-  };
+  aggregate() {}
+
+  logResults(): void {
+    // promotions facts
+    console.log('PROMOTIONS FACTS:');
+    console.log(
+      'How often a piece is promoted to different ambiguous piece types:'
+    ),
+      console.table(this.promotionMap);
+    console.log('How often unambiguous piece is promoted:'),
+      console.table(this.promotionMap);
+    console.log(
+      '=============================================================='
+    );
+    console.log('\n');
+  }
 }
diff --git a/tests/metrics.test.ts b/tests/metrics.test.ts
index 944e11f..e6d6ab5 100644
--- a/tests/metrics.test.ts
+++ b/tests/metrics.test.ts
@@ -7,6 +7,7 @@ import {
 } from '../src/metrics/captures';
 import { MoveDistanceMetric } from '../src/metrics/distances';
 import { getGameWithMostMoves } from '../src/metrics/moves';
+import { PromotionMetric } from '../src/metrics/promotions';
 
 // convert PGN string to GameHistoryObject
 export function pgnToGameHistory(pgn: string) {
@@ -331,7 +332,6 @@ describe('All Tests', () => {
 
       kdrMetric.processGame(Array.from(cjsmin.historyGenerator(game[0].moves)));
 
-      console.log(kdrMetric.KDAssistsMap['ng'].kills);
       expect(kdrMetric.KDAssistsMap['ng'].kills).toEqual(3);
     });
   });
@@ -351,4 +351,110 @@ describe('All Tests', () => {
       expect(result.maxNumMoves).toEqual(24);
     });
   });
+
+  describe('PromotionMetric', () => {
+    const promotionMetric = new PromotionMetric();
+
+    afterEach(() => {
+      promotionMetric.clear();
+    });
+
+    it('should update the promotion map when a promotion occurs', () => {
+      const moves = [
+        {
+          move: {
+            originalString: 'e8=Q',
+            color: 'b',
+            from: 'e7',
+            to: 'e8',
+            piece: 'p',
+            flags: 'p',
+            promotion: 'q',
+            uas: 'pe',
+          },
+          board: [],
+        },
+        {
+          move: {
+            originalString: 'a2=a1',
+            color: 'w',
+            from: 'a2',
+            to: 'a1',
+            piece: 'p',
+            flags: 'p',
+            promotion: 'q',
+            uas: 'PA',
+          },
+        },
+        {
+          move: {
+            originalString: 'b7=b8',
+            color: 'b',
+            from: 'b7',
+            to: 'b8',
+            piece: 'p',
+            flags: 'p',
+            promotion: 'r',
+            uas: 'pb',
+          },
+        },
+      ].map((entry) => {
+        return {
+          move: entry.move as any, // cast to match type checks in the processGame handler
+          board: [],
+        };
+      });
+
+      promotionMetric.processGame(moves);
+
+      expect(promotionMetric.promotionMap.pe.q).toEqual(1);
+      expect(promotionMetric.promotionMap.PA.q).toEqual(1);
+      expect(promotionMetric.promotionMap.pb.r).toEqual(1);
+    });
+
+    it('should not update the promotion map when a promotion does not occur', () => {
+      const moves = [
+        {
+          move: {
+            originalString: 'e4',
+            color: 'w',
+            from: 'e2',
+            to: 'e4',
+            piece: 'p',
+            flags: 'b',
+            uas: 'PE',
+          },
+        },
+        {
+          move: {
+            originalString: 'e5',
+            color: 'b',
+            from: 'e7',
+            to: 'e5',
+            piece: 'p',
+            flags: 'n',
+            uas: 'pe',
+          },
+        },
+      ].map((entry) => {
+        return {
+          move: entry.move as any, // cast to match type checks in the processGame handler
+          board: [],
+        };
+      });
+
+      promotionMetric.processGame(moves);
+      let promoTotal = 0;
+
+      for (const k of Object.keys(promotionMetric.promotionMap)) {
+        for (const promoCount of Object.values(
+          promotionMetric.promotionMap[k]
+        )) {
+          promoTotal += promoCount as number;
+        }
+      }
+
+      expect(promoTotal).toEqual(0);
+    });
+  });
 });