src/app/components/promotion-dialog/promotion-dialog.component.css

@@ -0,0 +1,131 @@
+.promotion-dialog-overlay {
+  position: fixed;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+  background: rgba(0, 0, 0, 0.5);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  opacity: 0;
+  visibility: hidden;
+  transition: opacity 0.2s, visibility 0.2s;
+  z-index: 1000;
+
+  &.open {
+    opacity: 1;
+    visibility: visible;
+  }
+}
+
+.promotion-dialog {
+  background: white;
+  border-radius: 8px;
+  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
+  max-width: 400px;
+  width: 90%;
+  animation: slideUp 0.3s ease;
+}
+
+@keyframes slideUp {
+  from {
+    opacity: 0;
+    transform: translateY(20px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
+}
+
+.promotion-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 20px;
+  border-bottom: 1px solid #e0e0e0;
+
+  h3 {
+    margin: 0;
+    font-size: 18px;
+    font-weight: 600;
+    color: #333;
+  }
+
+  .close-btn {
+    background: none;
+    border: none;
+    font-size: 24px;
+    cursor: pointer;
+    color: #999;
+    padding: 0;
+    width: 30px;
+    height: 30px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    transition: color 0.2s;
+
+    &:hover {
+      color: #333;
+    }
+  }
+}
+
+.promotion-body {
+  padding: 20px;
+}
+
+.promotion-prompt {
+  margin: 0 0 20px 0;
+  text-align: center;
+  color: #666;
+  font-size: 14px;
+}
+
+.promotion-options {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 12px;
+}
+
+.promotion-button {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  padding: 16px;
+  background: #f5f5f5;
+  border: 2px solid #ddd;
+  border-radius: 6px;
+  cursor: pointer;
+  transition: all 0.2s;
+  font-family: inherit;
+
+  &:hover {
+    background: #e8e8e8;
+    border-color: #999;
+    transform: translateY(-2px);
+    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
+  }
+
+  &:active {
+    transform: translateY(0);
+    box-shadow: none;
+  }
+
+  .piece-symbol {
+    font-size: 32px;
+    line-height: 1;
+  }
+
+  .piece-label {
+    font-size: 12px;
+    font-weight: 500;
+    color: #666;
+    text-transform: uppercase;
+    letter-spacing: 0.5px;
+  }
+}

src/app/components/promotion-dialog/promotion-dialog.component.html

@@ -0,0 +1,26 @@
+<div class="promotion-dialog-overlay" [class.open]="isOpen">
+  <div class="promotion-dialog">
+    <div class="promotion-header">
+      <h3>Pawn Promotion</h3>
+      <button class="close-btn" (click)="close()" aria-label="Close">&times;</button>
+    </div>
+    
+    <div class="promotion-body">
+      <p class="promotion-prompt">Choose a piece to promote your pawn to:</p>
+      
+      <div class="promotion-options">
+        @for (piece of promotionPieces; track piece.type) {
+          <button
+            class="promotion-button"
+            [attr.data-piece]="piece.type"
+            (click)="selectPromotion(piece.type)"
+            [title]="piece.label"
+          >
+            <span class="piece-symbol">{{ piece.symbol }}</span>
+            <span class="piece-label">{{ piece.label }}</span>
+          </button>
+        }
+      </div>
+    </div>
+  </div>
+</div>

src/app/components/promotion-dialog/promotion-dialog.component.ts

@@ -0,0 +1,39 @@
+import { Component, EventEmitter, Input, Output } from '@angular/core';
+import { CommonModule } from '@angular/common';
+
+type PromotionPieceType = 'queen' | 'rook' | 'bishop' | 'knight';
+interface PromotionPieceOption {
+  type: PromotionPieceType;
+  label: string;
+  symbol: string;
+}
+
+@Component({
+  selector: 'app-promotion-dialog',
+  standalone: true,
+  imports: [CommonModule],
+  templateUrl: './promotion-dialog.component.html',
+  styleUrl: './promotion-dialog.component.css'
+})
+export class PromotionDialogComponent {
+  @Input() isOpen = false;
+  @Output() promotionSelected = new EventEmitter<PromotionPieceType>();
+  @Output() closed = new EventEmitter<void>();
+
+  promotionPieces: PromotionPieceOption[] = [
+    { type: 'queen', label: 'Queen', symbol: '♕' },
+    { type: 'rook', label: 'Rook', symbol: '♖' },
+    { type: 'bishop', label: 'Bishop', symbol: '♗' },
+    { type: 'knight', label: 'Knight', symbol: '♘' }
+  ];
+
+  selectPromotion(type: PromotionPieceType): void {
+    this.promotionSelected.emit(type);
+    this.isOpen = false;
+  }
+
+  close(): void {
+    this.closed.emit();
+    this.isOpen = false;
+  }
+}

src/app/pages/game/game.component.html

@@ -1,4 +1,10 @@
 <main class="game-shell">
+  <app-promotion-dialog
+    [isOpen]="facade.isPromotionDialogOpen"
+    (promotionSelected)="facade.onPromotionSelected($event)"
+    (closed)="facade.onPromotionClosed()"
+  />
+
   <section class="game-card">
     <header class="mb-3">
       <a routerLink="/" class="back-link">Back</a>

src/app/pages/game/game.component.ts

@@ -4,13 +4,14 @@ import { takeUntilDestroyed } from '@angular/core/rxjs-interop';
 import { FormsModule } from '@angular/forms';
 import { ActivatedRoute, RouterLink } from '@angular/router';
 import { ChessBoardComponent } from '../../components/chess-board/chess-board.component';
-  import { InputCardComponent } from '../../components/input-card/input-card.component';
+import { InputCardComponent } from '../../components/input-card/input-card.component';
+import { PromotionDialogComponent } from '../../components/promotion-dialog/promotion-dialog.component';
 import { GameFacade } from './game.facade';
 
 @Component({
   selector: 'app-game',
   standalone: true,
-  imports: [CommonModule, FormsModule, RouterLink, ChessBoardComponent, InputCardComponent],
+  imports: [CommonModule, FormsModule, RouterLink, ChessBoardComponent, InputCardComponent, PromotionDialogComponent],
   providers: [GameFacade],
   templateUrl: './game.component.html',
   styleUrl: './game.component.css'

src/app/pages/game/game.facade.ts

@@ -1,7 +1,7 @@
 import { DestroyRef, Injectable, OnDestroy, inject } from '@angular/core';
 import { takeUntilDestroyed } from '@angular/core/rxjs-interop';
 import { getErrorMessage } from '../../core/http/error-message.util';
-import { GameFull, GameState, GameStreamEvent } from '../../models/game.models';
+import { GameFull, GameState, GameStreamEvent, LegalMove } from '../../models/game.models';
 import { GameApiService } from '../../services/game-api.service';
 import { BotMoveService } from '../../services/bot-move.service';
 import { GameCompletionService } from '../../services/game-completion.service';
@@ -20,12 +20,14 @@ export class GameFacade implements OnDestroy {
   loading = true;
   gameCompletionMessage = '';
   isGameFinished = false;
+  isPromotionDialogOpen = false;
 
   private boardSelection: BoardSelection = {
     selectedSquare: null,
     highlightedSquares: [],
     selectedSquareMoves: []
   };
+  private pendingPromotionMoves: LegalMove[] = [];
 
   private readonly gameApi = inject(GameApiService);
   private readonly destroyRef = inject(DestroyRef);
@@ -66,6 +68,15 @@ export class GameFacade implements OnDestroy {
     if (this.boardSelection.selectedSquare && this.boardSelection.highlightedSquares.includes(square)) {
       const selectedMove = this.boardSelection.selectedSquareMoves.find((move) => move.to === square);
       if (selectedMove) {
+        // If multiple promotion outcomes exist for the target, ask player to choose one.
+        const promotionMoves = this.boardSelection.selectedSquareMoves.filter(
+          (move) => move.to === square && !!move.promotion
+        );
+        if (promotionMoves.length > 0) {
+          this.pendingPromotionMoves = promotionMoves;
+          this.isPromotionDialogOpen = true;
+          return;
+        }
         this.moveInput = selectedMove.uci;
         this.submitMove();
       }
@@ -134,6 +145,28 @@ export class GameFacade implements OnDestroy {
       });
   }
 
+  onPromotionSelected(promotionPiece: 'queen' | 'rook' | 'bishop' | 'knight'): void {
+    const selectedPromotionMove = this.pendingPromotionMoves.find((move) => move.promotion === promotionPiece);
+    if (!selectedPromotionMove) {
+      this.errorMessage = 'Selected promotion move is unavailable.';
+      this.isPromotionDialogOpen = false;
+      this.pendingPromotionMoves = [];
+      return;
+    }
+
+    this.moveInput = selectedPromotionMove.uci;
+    this.isPromotionDialogOpen = false;
+    this.boardSelection = this.boardSelectionService.clearSelection();
+    this.pendingPromotionMoves = [];
+    this.submitMove();
+  }
+
+  onPromotionClosed(): void {
+    this.isPromotionDialogOpen = false;
+    this.boardSelection = this.boardSelectionService.clearSelection();
+    this.pendingPromotionMoves = [];
+  }
+
   importFen(): void {
     this.errorMessage = '';
     this.importService.importFen(