""" this file contains all details of game state and other parametrs """ class GameState(): def __init__(self,board=[[]]): self.board=[['bR','bN','bB','bQ','bK','bB','bN','bR'], ['bp','bp','bp','bp','bp','bp','bp','bp'], ['--','--','--','--','--','--','--','--'], ['--','--','--','--','--','--','--','--'], ['--','--','--','--','--','--','--','--'], ['--','--','--','--','--','--','--','--'], ['wp','wp','wp','wp','wp','wp','wp','wp'], ['wR','wN','wB','wQ','wK','wB','wN','wR'] ] if self.is_valid_board(board): self.board=board self.whiteToMove=True self.moveLog=[] self.knight_directions=[(-2, -1), (-1, -2), (-2, 1), (-1, 2), (2, -1), (1, -2), (2, 1), (1, 2)] self.bishop_directions= [(-1,-1),(-1,1),(1,-1),(1,1)] self.king_directions=[(-1,0),(0,-1),(1,0),(0,1),(-1,-1),(-1,1),(1,-1),(1,1)] self.check_mate = False self.steale_mate = False self.inheck = False # if king is in check this will be True self.pins=[] # if any peice stopping the check and if u move them u gona get check self.checks=[] # possible checks # we need to keep track of squares where u can eliminate if u took double move in the first place #that move name is empassant move # we can have dictionary to store functions self.protects=[[]] self.threatens =[[]] self.peices_can_move_to = [[]] self.move_functions={'p':self.get_pawn_moves, 'R':self.get_rook_moves, 'N':self.get_knight_moves, 'B':self.get_bishop_moves, 'K':self.get_king_moves, 'Q':self.get_queen_moves } #solution 1 to checks is keep track of kings location self.black_king_location=(0,4) self.white_king_location=(7,4) # we need to keep track of squares where u can eliminate if u took double move in the first place #that move name is empassant move # we can have dictionary to store functions self.empassant_moves=() #square for which empassant move is possible self.current_castling_rights = Castling_Rights(True,True,True,True) self.castle_rights_log=[Castling_Rights(self.current_castling_rights.wks,self.current_castling_rights.wqs,self.current_castling_rights.bks,self.current_castling_rights.bqs)] self.empassant_possible_log=[self.empassant_moves] self.update_state_variables() # when current castling rights modified it creates new object and pt it in log ''' To castle, your king and the chosen rook must not have moved, there must be no pieces between them, the king cannot be in or pass through check, and the king must not end up in check. castle must be first move to both king and rook this is the only move where two peice move ''' def make_move(self,move): #this is not for castling and pawn promotion just to add it for squares self.board[move.start_row][move.start_col]= '--' self.board[move.end_row][move.end_col]= move.peice_moved if move.peice_moved=='bK': self.black_king_location= (move.end_row,move.end_col) if move.peice_moved=="wK": self.white_king_location= (move.end_row,move.end_col) if move.is_pawn_promotion: self.board[move.end_row][move.end_col] = move.peice_moved[0]+ move.promotion_choice #castle move if move.castle: if move.end_col - move.start_col ==2: #king side col self.board [move.end_row][move.end_col-1]= self.board[move.end_row][move.end_col+1] self.board[move.end_row][move.end_col+1]='--' else: self.board [move.end_row][move.end_col+1]= self.board[move.end_row][move.end_col-2] #2 squares aqay from it starts self.board[move.end_row][move.end_col-2]='--' #empassant move if move.is_empassant_move: # remove square that is not captured but on the road self.board[move.start_row][move.end_col] = '--' # capturing the pawn #update empassant possible #only in the case if move.peice_moved[1] == 'p' and abs(move.start_row-move.end_row)==2: self.empassant_moves=( (move.start_row + move.end_row)//2 ,move.end_col ) else: self.empassant_moves = () #update castling rights whenever is is king or rook moves self.update_castle_rights(move) self.castle_rights_log.append(Castling_Rights(self.current_castling_rights.wks,self.current_castling_rights.wqs,self.current_castling_rights.bks,self.current_castling_rights.bqs)) self.empassant_possible_log.append(self.empassant_moves) self.moveLog.append(move) self.whiteToMove = not self.whiteToMove #switch turns ''' undo the previous move made ''' def undo_move(self): if len(self.moveLog): l_move = self.moveLog.pop() self.whiteToMove = not self.whiteToMove self.board[l_move.end_row][l_move.end_col]=l_move.peice_captured self.board[l_move.start_row][l_move.start_col]=l_move.peice_moved move=l_move if move.peice_moved=='bK': self.black_king_location= (move.start_row,move.start_col) if move.peice_moved=="wK": self.white_king_location= (move.start_row,move.start_col) if move.is_empassant_move: self.board[l_move.end_row][l_move.end_col] = '--' #leave end row and column as it is self.board[l_move.start_row][l_move.end_col]= move.peice_captured self.empassant_possible_log.pop() self.empassant_moves = self.empassant_possible_log[-1] if move.castle: if move.end_col - move.start_col ==2: #king side col self.board [move.end_row][move.end_col+1]= self.board[move.end_row][move.end_col-1] self.board[move.end_row][move.end_col-1]='--' else: self.board [move.end_row][move.end_col-2]= self.board[move.end_row][move.end_col+1] #2 squares aqay from it starts self.board[move.end_row][move.end_col+1]='--' ## undo the castling rights self.castle_rights_log.pop() #get rid of new castle rights self.current_castling_rights = self.castle_rights_log[-1] #undo checkmate move self.check_mate = False self.steale_mate = False else: print("this is our starting move ") #if u move then it might be check to u so need to check these possiblities #so we need to generate possible moves in next turn abd based on that we need to move def update_state_variables(self): # Ensure move log is empty for a fresh board self.moveLog = [] # Initialize game status flags self.whiteToMove = True self.checkmate = False self.stalemate = False self.in_check = False self.pins = [] self.checks = [] self.protects = [] self.threatens = [] self.pieces_can_move_to = [] # Update king locations by scanning the board self.white_king_location = None self.black_king_location = None for row in range(8): for col in range(8): if self.board[row][col] == 'wK': self.white_king_location = (row, col) if self.board[row][col] == 'bK': self.black_king_location = (row, col) # Set default king locations if not found (for standard board) if not self.white_king_location: self.white_king_location = (7, 4) if not self.black_king_location: self.black_king_location = (0, 4) # Reset en passant self.empassant_moves = () self.empassant_possible_log = [()] # Set castling rights based on piece positions self.current_castling_rights = Castling_Rights(False, False, False, False) if self.white_king_location == (7, 4): if self.board[7][0] == 'wR': self.current_castling_rights.wqs = True if self.board[7][7] == 'wR': self.current_castling_rights.wks = True if self.black_king_location == (0, 4): if self.board[0][0] == 'bR': self.current_castling_rights.bqs = True if self.board[0][7] == 'bR': self.current_castling_rights.bks = True self.castle_rights_log = [Castling_Rights( self.current_castling_rights.wks, self.current_castling_rights.wqs, self.current_castling_rights.bks, self.current_castling_rights.bqs )] # Calculate pins, checks, and in_check self.incheck,self.pins,self.checks = self.check_for_pins_and_checks() def is_valid_board(self, board): if len(board) != 8: return False valid_pieces = {'bR', 'bN', 'bB', 'bQ', 'bK', 'bp', 'wR', 'wN', 'wB', 'wQ', 'wK', 'wp', '--'} white_kings = 0 black_kings = 0 for row in range(8): if len(board[row]) != 8: return False for col in range(8): cell = board[row][col] if cell not in valid_pieces: return False if cell == 'wK': white_kings += 1 if cell == 'bK': black_kings += 1 # No pawns on promotion ranks if row in (0, 7) and cell[1] == 'p': return False if white_kings != 1 or black_kings != 1: return False return True ''' all moves including checks ''' def update_castle_rights(self,move): if move.peice_moved=='wK': self.current_castling_rights.wks=False self.current_castling_rights.wqs=False elif move.peice_moved=='bK': self.current_castling_rights.bks=False self.current_castling_rights.bqs=False elif move.peice_moved=='wR' and move.start_row==0: if move.start_col==7: self.current_castling_rights.wks=False elif move.start_col==0: self.current_castling_rights.wqs=False elif move.peice_moved=='bR' and move.start_row==7: if move.start_col==7: self.current_castling_rights.bks=False elif move.start_col==0: self.current_castling_rights.bqs=False # if rook is captured if move.peice_captured == 'wR': if move.end_row == 7: if move.end_col == 0: self.current_castling_rights.wqs=False elif move.end_col == 7: self.current_castling_rights.wks = False elif move.peice_captured == 'bR': if move.end_row == 0: if move.end_col == 0: self.current_castling_rights.bqs=False elif move.end_col == 7: self.current_castling_rights.bks = False def is_valid_square(self,r,c): if r>=0 and r<=7 and c>=0 and c<=7: return True else: return False def king_safety(self, color): board = self.board score = 0 # Find king position king_pos = None for r in range(8): for c in range(8): if board[r][c] == color + 'K': king_pos = (r, c) break if king_pos: break if not king_pos: return 0 # King missing? shouldn't happen. r, c = king_pos # Pawn shield (pawns in front of king) if color == 'w': pawn_row = r - 1 if pawn_row >= 0: for dc in [-1, 0, 1]: cc = c + dc if 0 <= cc < 8: if board[pawn_row][cc] == 'wp': score += 30 # strong pawn shield elif board[pawn_row][cc] == '--': score -= 15 # weak if missing else: # black pawn_row = r + 1 if pawn_row < 8: for dc in [-1, 0, 1]: cc = c + dc if 0 <= cc < 8: if board[pawn_row][cc] == 'bp': score += 30 elif board[pawn_row][cc] == '--': score -= 15 # Open file penalty (if no pawn in king’s file) file_has_pawn = False for rr in range(8): if board[rr][c] == color + 'p': file_has_pawn = True break if not file_has_pawn: score -= 40 # open file in front of king is dangerous # Enemy attacks around the king (adjacent squares) king_zone = [(r + dr, c + dc) for dr in [-1, 0, 1] for dc in [-1, 0, 1] if not (dr == 0 and dc == 0)] enemy_color = 'w' if color == 'b' else 'b' for (rr, cc) in king_zone: if 0 <= rr < 8 and 0 <= cc < 8: self.whiteToMove = not self.whiteToMove moves = self.get_all_possible_moves() for move in moves: if (move.end_row, move.end_col) == (rr, cc): score -= 20 # enemy attacks near king self.whiteToMove = not self.whiteToMove return score def get_valid_moves(self): #naive solution #this is very inefficient and generate all moves in two levels for check #generate all moves # for all moves try to generate next possible moves #for each opponent move check if he can attack your king #if my king is attacked then it is invalid # # if u are removing then it is better to traverse list backwards # #indexes wont shift # for i in range(len(moves)-1,-1,-1): # self.make_move(moves[i]) # #swap turns so this will check my check moves # self.whiteToMove = not self.whiteToMove # if self.has_check(): # moves.remove(moves[i]) # self.whiteToMove = not self.whiteToMove # self.undo_move() # decide algo2 #check for all verticals,horizantals,diagnols and which peices can attack king #check for kinght attacks #check for direct checks #check for if i move this peice can i got any check #ckeck for check where u have to move self.incheck,self.pins,self.checks = self.check_for_pins_and_checks() if self.whiteToMove: king_row,king_col = self.white_king_location else: king_row,king_col = self.black_king_location if self.incheck: if len(self.checks)==1: moves = self.get_all_possible_moves() check_row,check_col,x_dist,y_dist = self.checks[0] peice_checking = self.board[check_row][check_col] valid_squares=[] if peice_checking[1]=='N': valid_squares=[(check_row,check_col)] else: for i in range(1,8): valid_square = (king_row + i*x_dist , king_col + i*y_dist) valid_squares.append(valid_square) if valid_square[0] == check_row and valid_square[1]==check_col: #once u get to peice and checks break for i in range(len(moves)-1,-1,-1): if moves[i].peice_moved[1] != 'K': if not ( moves[i].end_row,moves[i].end_col) in valid_squares: #these moves not blobk check so no need moves.remove(moves[i]) else: # double check king has to move moves=[] moves=self.get_king_moves(king_row,king_col,moves) else: moves = self.get_all_possible_moves() # no check so all moves are fine if self.whiteToMove: self.get_castle_moves(self.white_king_location[0],self.white_king_location[1],moves,'w') else: self.get_castle_moves(self.black_king_location[0],self.black_king_location[1],moves,'b') if len(moves)==0: #either check mate or stealmate if self.has_check(): self.check_mate=True else: self.steale_mate=True else: self.check_mate=False self.steale_mate=False return moves ''' determine if current player in check if player in check need to remove check otherwise game over ''' def check_for_pins_and_checks(self): pins=[] checks=[] incheck=False if self.whiteToMove: my_color='w' enemy_color='b' start_row,start_col = self.white_king_location else: my_color='b' enemy_color='w' start_row,start_col = self.black_king_location for j,(x,y) in enumerate(self.king_directions): possible_pins = () for i in range(1,8): new_x,new_y = start_row+ x*i , start_col + y*i if self.is_valid_square(new_x,new_y): end_peice = self.board[new_x][new_y] if end_peice[0]==my_color and end_peice[1]!='K': if possible_pins == (): #first pin could be found possible_pins = (new_x,new_y,x,y) # else: # 2nd allied peice or no pins break break elif end_peice[0] == enemy_color : type = end_peice[1] #5 possibilities here in this complex situation # orthogonnaly rook # diagonally king #anywhere king # pawn or king at one square distance #any direction 1 square away and peice is a king (necessary to not to go in other king's controlled square) if (0<=j<=3 and type=='R') or \ (4<=j<=7 and type=='B') or \ (type=='Q') or \ (i==1 and type=='K') or \ (i==1 and type=='p' and ( (enemy_color=='w' and j in [6,7]) or (enemy_color=='b' and j in [4,5]) )): if possible_pins == (): incheck = True checks.append((new_x,new_y,x,y)) else: pins.append(possible_pins) break else: break else: break for x,y in self.knight_directions: new_x,new_y = start_row + x,start_col + y if self.is_valid_square(new_x,new_y): end_peice = self.board[new_x][new_y] if end_peice[1]== 'N' and end_peice[0]==enemy_color: #kinght attack king incheck=True checks.append((new_x,new_y,x,y)) return incheck,pins,checks def has_check(self): if self.whiteToMove: return self.square_under_attack(self.white_king_location[0],self.white_king_location[1]) else: return self.square_under_attack(self.black_king_location[0],self.black_king_location[1]) pass ''' this determines if enemy can attack this square ''' def square_under_attack(self,r,c): self.whiteToMove = not self.whiteToMove #change to my opponent opp_moves = self.get_all_possible_moves() for move in opp_moves: if move.end_row == r and move.end_col == c: self.whiteToMove = not self.whiteToMove return True self.whiteToMove = not self.whiteToMove return False ''' all moves without checks for each possible move check to see if it is a valid move by doing the following make a move generate moves for opposite player see if any of ur moves ur king is attacked king is move add valid move to the list ''' def get_all_possible_moves(self): moves=[] for r in range(len(self.board)): for c in range(len(self.board[r])): turn = self.board[r][c][0] if (turn == 'w' and self.whiteToMove) or (turn=='b' and not self.whiteToMove): peice = self.board[r][c][1] self.move_functions[peice](r,c,moves) #calls the appropriate move functions return moves ''' this func return the pawn moves for particular pawn ''' def get_pawn_moves(self,r,c,moves: list): peice_pinned = False pin_direction = () for i in range(len(self.pins)-1,-1,-1): if self.pins[i][0] == r and self.pins[i][1]==c: peice_pinned=True pin_direction = (self.pins[i][2],self.pins[i][3]) self.pins.remove(self.pins[i]) break if self.whiteToMove: if r == 6 : if not peice_pinned or pin_direction == (-1,0): if self.board[4][c]=='--' and self.board[5][c]=='--': moves.append(Move((6,c),(4,c),self.board)) if self.board[r-1][c]=='--': if not peice_pinned or pin_direction == (-1,0): moves.append(Move((r,c),(r-1,c),self.board)) if c>=1: if not peice_pinned or pin_direction == (-1,-1): if self.board[r-1][c-1][0]=='b': moves.append(Move((r,c),(r-1,c-1),self.board)) elif (r-1,c-1)==self.empassant_moves: moves.append(Move((r,c),(r-1,c-1),self.board,is_empassant_move=True)) if c<=6 : if not peice_pinned or pin_direction == (-1,+1): if self.board[r-1][c+1][0]=='b': moves.append(Move((r,c),(r-1,c+1),self.board)) elif (r-1,c+1)==self.empassant_moves: moves.append(Move((r,c),(r-1,c+1),self.board,is_empassant_move=True)) else : if r<=6: if not peice_pinned or pin_direction == (1,0): if self.board[r+1][c]=='--': moves.append(Move((r,c),(r+1,c),self.board)) if r == 1: if self.board[3][c]=='--' and self.board[2][c]=='--': moves.append(Move((1,c),(3,c),self.board)) if not peice_pinned or pin_direction == (1,-1): if c>=1: if self.board[r+1][c-1][0]=='w': moves.append(Move((r,c),(r+1,c-1),self.board)) elif (r+1,c-1)==self.empassant_moves: moves.append(Move((r,c),(r+1,c-1),self.board,is_empassant_move=True)) if not peice_pinned or pin_direction == (1,1): if c<=6 : if self.board[r+1][c+1][0]=='w': moves.append(Move((r,c),(r+1,c+1),self.board)) elif (r+1,c+1)==self.empassant_moves: moves.append(Move((r,c),(r+1,c+1),self.board,is_empassant_move=True)) return moves ''' this func return the rook moves for particular rook ''' def get_rook_moves(self,r,c,moves): peice_pinned = False pin_direction = () for i in range(len(self.pins)-1,-1,-1): if self.pins[i][0] == r and self.pins[i][1]==c: peice_pinned=True pin_direction = (self.pins[i][2],self.pins[i][3]) if self.board[r][c][1]!='Q': #cannot remove queen from pin on rook moves ,onl remove it from bishop moves self.pins.remove(self.pins[i]) break if self.whiteToMove: ur_symbol= 'w' opp = 'b' else: ur_symbol= 'b' opp = 'w' for x,y in [(-1,0),(1,0),(0,1),(0,-1)]: for i in range(1,8): new_x,new_y = r + x*i ,c + y*i if not self.is_valid_square(new_x,new_y): break else: if not peice_pinned or pin_direction == (x,y) or pin_direction == (-x,-y): if self.board[new_x][new_y][0]=='-': moves.append(Move((r,c),(new_x,new_y),self.board)) elif self.board[new_x][new_y][0]==opp: moves.append(Move((r,c),(new_x,new_y),self.board)) break else : break return moves ''' this func return the knight moves for particular rook ''' def get_knight_moves(self,r,c,moves): peice_pinned = False for i in range(len(self.pins)-1,-1,-1): if self.pins[i][0] == r and self.pins[i][1]==c: peice_pinned=True self.pins.remove(self.pins[i]) break if self.whiteToMove: ur_symbol= 'w' opp = 'b' else: ur_symbol= 'b' opp = 'w' for x,y in self.knight_directions: new_x,new_y = r+x,c+y if (self.is_valid_square(new_x,new_y)): if not peice_pinned: if self.board[new_x][new_y][0]!=ur_symbol: moves.append(Move((r,c),(new_x,new_y),self.board)) return moves ''' this func return the bishop moves for particular rook ''' def get_bishop_moves(self,r,c,moves): peice_pinned = False pin_direction = () for i in range(len(self.pins)-1,-1,-1): if self.pins[i][0] == r and self.pins[i][1]==c: peice_pinned=True pin_direction = (self.pins[i][2],self.pins[i][3]) self.pins.remove(self.pins[i]) break if self.whiteToMove: ur_symbol= 'w' opp = 'b' else: ur_symbol= 'b' opp = 'w' for x,y in self.bishop_directions: for i in range(1,8): new_x,new_y = r + x*i ,c + y*i if not self.is_valid_square(new_x,new_y): break else: if not peice_pinned or pin_direction == (x,y) or pin_direction == (-x,-y): if self.board[new_x][new_y][0]=='-': moves.append(Move((r,c),(new_x,new_y),self.board)) elif self.board[new_x][new_y][0]==opp: moves.append(Move((r,c),(new_x,new_y),self.board)) break else : break return moves ''' this func return the king moves for particular king ''' def get_king_moves(self,r,c,moves): if self.whiteToMove: ur_symbol= 'w' opp = 'b' else: ur_symbol= 'b' opp = 'w' for x,y in self.king_directions: new_x,new_y = r+x,c+y if (self.is_valid_square(new_x,new_y)): if self.board[new_x][new_y][0]!=ur_symbol: if ur_symbol == 'w': self.white_king_location = (new_x,new_y) else: self.black_king_location = (new_x,new_y) incheck,pins,checks = self.check_for_pins_and_checks() #check for pins and checks and if not add the move if not incheck: moves.append(Move((r,c),(new_x,new_y),self.board)) if ur_symbol == 'w': self.white_king_location = (r,c) else: self.black_king_location = (r,c) # place king in original position return moves ''' this func return the queen moves for particular rook ''' def get_queen_moves(self,r,c,moves): return self.get_bishop_moves(r,c,moves) + self.get_rook_moves(r,c,moves) ''' generate all castle moves ''' def get_castle_moves(self,r,c,moves,my_color): if self.square_under_attack(r,c): return # cannot castle if king is in check if (self.whiteToMove and self.current_castling_rights.wks) or (not self.whiteToMove and self.current_castling_rights.bks): self.king_side_castle_moves(r,c,moves,my_color) if (self.whiteToMove and self.current_castling_rights.wqs) or (not self.whiteToMove and self.current_castling_rights.bqs): self.queen_side_castle_moves(r,c,moves,my_color) def king_side_castle_moves(self,r,c,moves,my_color): if c + 2 <= 7: if self.board[r][c+1]== '--' and self.board[r][c+2]== '--': if not self.square_under_attack(r,c+1) and not self.square_under_attack(r,c+2): moves.append ( Move((r,c),(r,c+2),self.board,castle=True)) def queen_side_castle_moves(self,r,c,moves,my_color): if c-3 >=0: if self.board[r][c-1]== '--' and self.board[r][c-2]== '--' and self.board[r][c-3]== '--': if not self.square_under_attack(r,c-1) and not self.square_under_attack(r,c-2) : moves.append ( Move((r,c),(r,c-2),self.board,castle=True)) ''' make castling right class other wise difficult to include it in main code ''' class Castling_Rights(): def __init__(self,wks,wqs,bks,bqs): self.bks=bks self.bqs=bqs self.wks=wks self.wqs=wqs class Move(): ranks_to_rows = { '1':7,'2':6,'3':5,'4':4,'5':3,'6':2,'7':1,'8':0} rows_to_ranks = {v:k for k,v in ranks_to_rows.items()} files_to_cols = {chr(97+i):i for i in range(8)} cols_to_files={v:k for k,v in files_to_cols.items()} def __init__(self,startsq,endsq,board,choice='Q',is_empassant_move=False,castle=False): #for undowing the move its better to store the board information self.start_row = startsq[0] self.start_col = startsq[1] self.end_row = endsq[0] self.end_col = endsq[1] self.peice_moved = board[self.start_row][self.start_col] self.peice_captured = board[self.end_row][self.end_col] self.is_pawn_promotion = False if (self.peice_moved == 'wp' and self.end_row==0) or (self.peice_moved == 'bp' and self.end_row==7): self.is_pawn_promotion=True self.promotion_choice =choice self.is_empassant_move=False if is_empassant_move: self.is_empassant_move=True self.peice_captured = 'wp' if self.peice_moved =='bp' else 'bp' self.castle=castle self.is_capture = self.peice_captured!='--' self.move_id = self.start_row*1000 + self.start_col * 100 + self.end_row * 10 + self.end_col # generate unique id and since all below 10 we can do this #have to tell python if two moves are equal ''' over writing a method other wise python check and they are two different objects ''' def __eq__(self, value): if isinstance(value,Move): return value.move_id == self.move_id return False def get_chess_notation(self): #make it to look move in chess notation return self.get_rank_file(self.start_row,self.start_col) + self.get_rank_file(self.end_row,self.end_col) def get_rank_file(self,r,c): return self.cols_to_files[c]+ self.rows_to_ranks[r] #first column than row def __str__(self): #castle move if self.castle: return "o-o" if self.end_col==6 else 'o-o-o' end_square = self.get_rank_file(self.end_row,self.end_col) #pawn move if self.peice_moved[1] == 'p': if self.is_capture: return self.cols_to_files[self.start_col] + 'x'+ end_square + f""" {self.peice_moved} from {self.get_rank_file(self.start_row, self.start_col)} to {self.get_rank_file(self.end_row, self.end_col)}""" else: return end_square+ f""" {self.peice_moved} from {self.get_rank_file(self.start_row, self.start_col)} to {self.get_rank_file(self.end_row, self.end_col)}""" # pawn promotion #Nbd2 both knights can move to d2 # for check and checkmate # peice moves move_string = self.peice_moved[1] if self.is_capture: move_string+='x' return move_string + end_square + f""" {self.peice_moved} from {self.get_rank_file(self.start_row, self.start_col)} to {self.get_rank_file(self.end_row, self.end_col)}"""