diff --git a/OOP_3B6_Project/src/backend/Board.java b/OOP_3B6_Project/src/backend/Board.java
index 932767b..8a8ca0d 100644
--- a/OOP_3B6_Project/src/backend/Board.java
+++ b/OOP_3B6_Project/src/backend/Board.java
@@ -353,3 +353,187 @@ public class Board {
 }
 
  
+//Add these methods to your Board class
+
+/**
+* Checks if the king of the specified color is in check
+* @param isWhiteKing true if checking for white king, false for black king
+* @return true if the king is in check, false otherwise
+*/
+public boolean isKingInCheck(boolean isWhiteKing) {
+ // First, find the king
+ Piece king = null;
+ for (Piece p : pieces) {
+     if (p.getType() == PieceType.King && p.isWhite() == isWhiteKing) {
+         king = p;
+         break;
+     }
+ }
+ 
+ if (king == null) {
+     return false; // No king found (shouldn't happen in a valid game)
+ }
+ 
+ // Check if any opponent piece can capture the king
+ for (Piece p : pieces) {
+     if (p.isWhite() != isWhiteKing) { // Opponent's piece
+         ArrayList<int[]> moves = computeLegalMoves(p);
+         for (int[] move : moves) {
+             if (move[0] == king.getX() && move[1] == king.getY()) {
+                 return true; // King is in check
+             }
+         }
+     }
+ }
+ 
+ return false;
+}
+
+public boolean isCheckmate() {
+ boolean currentPlayerIsWhite = isTurnWhite();
+ 
+ // First, check if the king is in check
+ if (!isKingInCheck(currentPlayerIsWhite)) {
+     return false; // Not in check, so definitely not in checkmate
+ }
+ 
+ // Try every possible move for the current player
+ for (Piece p : pieces) {
+     if (p.isWhite() == currentPlayerIsWhite) {
+         ArrayList<int[]> moves = computeLegalMoves(p);
+         for (int[] move : moves) {
+             // Create a copy of the board and try the move
+             Board tempBoard = new Board(this);
+             
+             // Create and play the move
+             Piece capturedPiece = null;
+             for (Piece target : tempBoard.getPieces()) {
+                 if (target.getX() == move[0] && target.getY() == move[1]) {
+                     capturedPiece = target;
+                     break;
+                 }
+             }
+             
+             Move testMove = new Move(
+                 p.getX(), p.getY(),
+                 move[0], move[1],
+                 p.isWhite(), p.getType(),
+                 capturedPiece
+             );
+             
+             tempBoard.playMove(testMove);
+             
+             // Check if the king is still in check after the move
+             if (!tempBoard.isKingInCheck(currentPlayerIsWhite)) {
+                 return false; // Found a move that escapes check
+             }
+         }
+     }
+ }
+ 
+ // If we've tried all moves and none escape check, it's checkmate
+ return true;
+}
+
+/**
+* Modified userTouch method to check for checkmate after each move
+*/
+public void userTouch(int x, int y) {
+ Piece clickedPiece = getPieceAt(x, y);
+ // No selection yet
+ if (selectedX == null || selectedY == null) {
+     if (clickedPiece != null && clickedPiece.isWhite() == isWhiteTurn) {
+         selectedX = x;
+         selectedY = y;
+         highlightedSquares = computeLegalMoves(clickedPiece);
+     }
+     return;
+ }
+ // Click again to unselect
+ if (selectedX == x && selectedY == y) {
+     selectedX = null;
+     selectedY = null;
+     highlightedSquares.clear();
+     return;
+ }
+ // Try to move
+ for (int[] move : highlightedSquares) {
+     if (move[0] == x && move[1] == y) {
+         Piece selectedPiece = getPieceAt(selectedX, selectedY);
+         Piece captured = getPieceAt(x, y);
+         // Store move for undo
+         Move m = new Move(
+             selectedX, selectedY, x, y,
+             selectedPiece.isWhite(), selectedPiece.getType(), captured
+         );
+         moveHistory.push(m);
+         removePieceAt(x, y); // capture
+         removePieceAt(selectedX, selectedY);
+         pieces.add(new Piece(x, y, selectedPiece.isWhite(), selectedPiece.getType()));
+         turnNumber++;
+         isWhiteTurn = !isWhiteTurn;
+         
+         // Check for checkmate after the move
+         if (isCheckmate()) {
+             // Use a JOptionPane to show a popup message
+             javax.swing.JOptionPane.showMessageDialog(
+                 null,
+                 (isWhiteTurn ? "Black" : "White") + " wins by checkmate!",
+                 "Checkmate",
+                 javax.swing.JOptionPane.INFORMATION_MESSAGE
+             );
+         }
+         // Also check if the opponent's king is in check (but not checkmate)
+         else if (isKingInCheck(isWhiteTurn)) {
+             javax.swing.JOptionPane.showMessageDialog(
+                 null,
+                 "Check!",
+                 "Check",
+                 javax.swing.JOptionPane.INFORMATION_MESSAGE
+             );
+         }
+         
+         break;
+     }
+ }
+ selectedX = null;
+ selectedY = null;
+ highlightedSquares.clear();
+}
+
+public void playMove(Move move) {
+ if (move == null) return;
+ // Store move for undo
+ moveHistory.push(move);
+ // Remove captured piece if any
+ if (move.getCapturedPiece() != null) {
+     removePieceAt(move.getToX(), move.getToY());
+ }
+ // Remove piece from original position
+ removePieceAt(move.getFromX(), move.getFromY());
+ // Add piece to new position
+ pieces.add(new Piece(move.getToX(), move.getToY(), move.isWhite(), move.getType()));
+ // Update turn
+ turnNumber++;
+ isWhiteTurn = !isWhiteTurn;
+ 
+ // Check for checkmate after the move
+ if (isCheckmate()) {
+     // Use a JOptionPane to show a popup message
+     javax.swing.JOptionPane.showMessageDialog(
+         null,
+         (isWhiteTurn ? "Black" : "White") + " wins by checkmate!",
+         "Checkmate",
+         javax.swing.JOptionPane.INFORMATION_MESSAGE
+     );
+ }
+ // Also check if the opponent's king is in check (but not checkmate)
+ else if (isKingInCheck(isWhiteTurn)) {
+     javax.swing.JOptionPane.showMessageDialog(
+         null,
+         "Check!",
+         "Check",
+         javax.swing.JOptionPane.INFORMATION_MESSAGE
+     );
+ }
+}
\ No newline at end of file