class ChessModel:
    def __init__(self):
        self.board = self.create_board()
        self.turn = "white"
    
    def create_board(self):
        # Simplified chess board representation
        board = [[" " for _ in range(8)] for _ in range(8)]
        # Initialize pawns
        board[1] = ["p" for _ in range(8)]
        board[6] = ["P" for _ in range(8)]
        # Initialize rooks
        board[0][0] = board[0][7] = "r"
        board[7][0] = board[7][7] = "R"
        # Initialize knights
        board[0][1] = board[0][6] = "n"
        board[7][1] = board[7][6] = "N"
        # Initialize bishops
        board[0][2] = board[0][5] = "b"
        board[7][2] = board[7][5] = "B"
        # Initialize queens
        board[0][3] = "q"
        board[7][3] = "Q"
        # Initialize kings
        board[0][4] = "k"
        board[7][4] = "K"
        return board

    def move(self, start_pos, end_pos):
        start_x, start_y = start_pos
        end_x, end_y = end_pos
        piece = self.board[start_x][start_y]
        self.board[start_x][start_y] = " "
        self.board[end_x][end_y] = piece
        self.turn = "black" if self.turn == "white" else "white"