function chessRules() {
	var checking = false;
	var letters = ["a", "b", "c", "d", "e", "f", "g", "h"];
	var letter = [];
	letter["a"] = 1;
	letter["b"] = 2;
	letter["c"] = 3;
	letter["d"] = 4;
	letter["e"] = 5;
	letter["f"] = 6;
	letter["g"] = 7;
	letter["h"] = 8;

	this.pawn = 
	function(fromX, fromY, color) {
		var toX;
		var toY;
		var toYlong;
		var fromXnum;
		var result = [];
		var mod;
		fromXnum = letter[fromX];
		// White pawns move "up", black move "down"
		if (color == "white") 
			mod = 1;
		else
			mod = -1;
		toX = fromX;
		toY = parseInt(fromY + mod);

		if (game.squares[toX][toY].piece == null) {
			if(!checking) {
				game.makeMove(fromX, fromY, toX, toY, false);
				if (!this.check(color)) {
					result.push(toX + toY);
				}
				game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
			} else result.push(toX + toY);
		}

		toYlong = parseInt(toY + mod);

		if (((fromY == 2 && color == "white") || (fromY == 7 && color == "black")) && game.squares[toX][toY].piece == null && game.squares[toX][toYlong].piece == null) {
			if(!checking) {
				game.makeMove(fromX, fromY, toX, toYlong, false);
				if (!this.check(color)) {
					result.push(toX + toYlong);
				}
				game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
			} else result.push(toX + toYlong);
		}

		if (fromXnum > 1) {
			toX = letters[fromXnum - 1 - 1];
			capturePiece = game.squares[toX][toY].piece;
			if (capturePiece != null && capturePiece.color != color) {
				if(!checking) {
					game.makeMove(fromX, fromY, toX, toY, true);
					if (!this.check(color)) {
						result.push(toX + toY);
					}
					game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
				} else result.push(toX + toY);
			}
			if (toX + toY == game.enPassant) {
				if(!checking) {
					game.makeMove(fromX, fromY, toX, toY, true);
					//document.write (toX + (toY + mod));
					game.squares[toX][toY - mod].piece.square = null;
					game.squares[toX][toY - mod].piece = null;
					if (!this.check(color)) {
						result.push(toX + toY);
					}
					game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
				} else result.push(toX + toY);
			}
		}

		if (fromXnum < 8) {
			toX = letters[fromXnum + 1 - 1];
			capturePiece = game.squares[toX][toY].piece;
			if (capturePiece != null && capturePiece.color != color && capturePiece != "king") {
				if(!checking) {
					game.makeMove(fromX, fromY, toX, toY, true);
					if (!this.check(color)) {
						result.push(toX + toY);
					}
					game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
				} else result.push(toX + toY);
			}
			if (toX + toY == game.enPassant) {
				if(!checking) {
					game.makeMove(fromX, fromY, toX, toY, true);
					game.squares[toX][toY - mod].piece.square = null;
					game.squares[toX][toY - mod].piece = null;
					if (!this.check(color)) {
						result.push(toX + toY);
					}
					game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
				} else result.push(toX + toY);
			}
		}

		return result;
	}
	
	this.knight =
	function (fromX, fromY, color) {
		var fromXnum;
		var toX;
		var toY;
		var toXnum;
		var result = [];
		fromXnum = letter[fromX];
		for (var i = -2; i <= 2; i++) {
			for (var j = -2; j <=2; j++) {
				if(Math.abs(i) != Math.abs(j) && i != 0 && j != 0) {
					toXnum = parseInt(fromXnum + i);
					toX = letters[toXnum - 1];
					toY = parseInt(fromY + j);
					if (toXnum > 0 && toXnum <= 8 && toY > 0 && toY <=8) {
						var pieceTo = game.squares[toX][toY].piece;
						if (pieceTo == null || pieceTo.color != color) {
							if(pieceTo != null)
								capture = true;
							else
								capture = false;
							if (!checking) {
								game.makeMove(fromX, fromY, toX, toY, capture);
								if (!this.check(color)) {
									result.push(toX + toY);
								}
								game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
							} else result.push(toX + toY);
						}
					}
				}
			}
		}
		return result;
	}
	
	this.bishop =
	function (fromX, fromY, color, range) {
		var toXnum;
		var toX;
		var toY;
		var fromXnum;
		if (range == undefined)
			range = 7;
		var result = [];
		fromXnum = letter[fromX];
		for (var i = 1; i <= range; i++) {
			var j = i;
			toXnum = parseInt(fromXnum + i);
			toX = letters[toXnum - 1];
			toY = parseInt(fromY + j);
			if (toXnum > 0 && toXnum <= 8 && toY > 0 && toY <=8) {
				var pieceTo = game.squares[toX][toY].piece;
				
				if (pieceTo == null || pieceTo.color != color) {
					if(pieceTo != null)
						capture = true;
					else
						capture = false;

					if (!checking) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						}
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					} else result.push(toX + toY);
				}
				
				if (pieceTo != null) {
					break;
				}
			}
		}
		for (var i = 1; i <= range; i++) {
			var j = -i;
			toXnum = parseInt(fromXnum + i);
			toX = letters[toXnum - 1];
			toY = parseInt(fromY + j);
			if (toXnum > 0 && toXnum <= 8 && toY > 0 && toY <=8) {
				var pieceTo = game.squares[toX][toY].piece;
				if (pieceTo == null || pieceTo.color != color) {
					if(pieceTo != null)
						capture = true;
					else
						capture = false;
					if (!checking) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						}
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					} else result.push(toX + toY);
				}
				if (pieceTo != null)
					break;
			}
		}
		for (var i = -1; i >= -range; i--) {
			var j = i;
			toXnum = parseInt(fromXnum + i);
			toX = letters[toXnum - 1];
			toY = parseInt(fromY + j);
			if (toXnum > 0 && toXnum <= 8 && toY > 0 && toY <=8) {
				var pieceTo = game.squares[toX][toY].piece;
				if (pieceTo == null || pieceTo.color != color) {
					if(pieceTo != null)
						capture = true;
					else
						capture = false;

					if (!checking) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						}
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					} else result.push(toX + toY);
				}
				if (pieceTo != null)
					break;
			}
		}
		for (var i = -1; i >= -range; i--) {
			var j = -i;
			toXnum = parseInt(fromXnum + i);
			toX = letters[toXnum - 1];
			toY = parseInt(fromY + j);
			if (toXnum > 0 && toXnum <= 8 && toY > 0 && toY <=8) {
				var pieceTo = game.squares[toX][toY].piece;
				if (pieceTo == null || pieceTo.color != color) {
					if(pieceTo != null)
						capture = true;
					else
						capture = false;
					if (!checking) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						}
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					} else result.push(toX + toY);
				}
				if (pieceTo != null)
					break;
			}
		}
		return result;
	}

	this.rook =
	function (fromX, fromY, color, range) {
		var toXnum;
		var toX;
		var toY;
		var fromXnum;
		if (range == undefined)
			range = 7;
		var result = [];
		fromXnum = letter[fromX];
		for (var i = 1; i <= range; i++) {
			toXnum = parseInt(fromXnum + i);
			toX = letters[toXnum - 1];
			toY = fromY;
			if (toXnum > 0 && toXnum <= 8 && toY > 0 && toY <=8) {
				var pieceTo = game.squares[toX][toY].piece;
				if (pieceTo == null || pieceTo.color != color) {
					if(pieceTo != null)
						capture = true;
					else
						capture = false;
					if (!checking) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						}
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					} else result.push(toX + toY);
				}
				if (pieceTo != null)
					break;
			}
		}
		for (var i = 1; i <= range; i++) {
			toXnum = fromXnum;
			toX = letters[toXnum - 1];
			toY = parseInt(fromY + i);
			if (toXnum > 0 && toXnum <= 8 && toY > 0 && toY <=8) {
				var pieceTo = game.squares[toX][toY].piece;
				if (pieceTo == null || pieceTo.color != color) {
					if(pieceTo != null)
						capture = true;
					else
						capture = false
					if (!checking) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						}
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					} else result.push(toX + toY);
				}
				if (pieceTo != null)
					break;
			}
		}
		for (var i = -1; i >= -range; i--) {
			toXnum = parseInt(fromXnum + i);
			toX = letters[toXnum - 1];
			toY = fromY;
			if (toXnum > 0 && toXnum <= 8 && toY > 0 && toY <=8) {
				var pieceTo = game.squares[toX][toY].piece;
				if (pieceTo == null || pieceTo.color != color) {
					if(pieceTo != null)
						capture = true;
					else
						capture = false;
					if (!checking) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						}
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					} else result.push(toX + toY);
				}
				if (pieceTo != null)
					break;
			}
		}
		for (var i = -1; i >= -range; i--) {
			toXnum = fromXnum;
			toX = letters[toXnum - 1];
			toY = parseInt(fromY + i);
			if (toXnum > 0 && toXnum <= 8 && toY > 0 && toY <=8) {
				var pieceTo = game.squares[toX][toY].piece;
				if (pieceTo == null || pieceTo.color != color) {
					if(pieceTo != null)
						capture = true;
					else
						capture = false;
					if (!checking) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						}
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					} else result.push(toX + toY);
				}
				if (pieceTo != null)
					break;
			}
		}
		return result;
	}
	
	this.queen =
	function (fromX, fromY, color) {
		return this.bishop(fromX, fromY, color).concat(this.rook(fromX, fromY, color));
	}

	this.king =
	function (fromX, fromY, color) {
		var toXnum;
		var toX;
		var toXpass;
		var toXpass2;
		var toY;
		var fromXnum;
		var result = [];
		fromXnum = letter[fromX];
		toY = fromY;
		if (game.castling != "-" && fromXnum == 5 && !checking && !this.check(color)) {
			if ((color == "white" && game.castling.match(/K/)) || (color == "black" && game.castling.match(/k/))) {
				toXnum = fromXnum ;
				toXpass = letters[toXnum + 1 - 1];
				toX = letters[toXnum + 2 - 1];
				if (game.squares[toXpass][toY].piece == null && game.squares[toX][toY].piece == null) {
					game.makeMove(fromX, fromY, toXpass, toY, capture);
					if (!this.check(color)) {
						passOk = true;
					} else
						passOk = false;
					game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					if (passOk) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						} 
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					}
				}
			}
			if ((color == "white" && game.castling.match(/Q/)) || (color == "black" && game.castling.match(/q/))) {
				toXnum = fromXnum ;
				toXpass = letters[toXnum - 1 - 1];
				toXpass2 = letters[toXnum - 3 - 1];
				toX = letters[toXnum - 2 - 1];
				if (game.squares[toXpass][toY].piece == null && game.squares[toX][toY].piece == null && game.squares[toXpass2][toY].piece == null) {
					game.makeMove(fromX, fromY, toXpass, toY, capture);
					if (!this.check(color)) {
						passOk = true;
					} else
						passOk = false;
					game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
					if (passOk) {
						game.makeMove(fromX, fromY, toX, toY, capture);
						if (!this.check(color)) {
							result.push(toX + toY);
						}
						game.loadFEN((variation == - 1 ? game.FENs[currMove] : game.varFENs[variation][varMove]));
						
					}
				}
			}
		}
		
		return result.concat(this.bishop(fromX, fromY, color, 1).concat(this.rook(fromX, fromY, color, 1)));
	}

	// Sees if game is in check state for the current player
	this.check = 
	function(color) {
		if (checking)
			return false;

		checking = true;
		kingX = game.pieces[game.getPiece("king", color)].square.x;
		kingY = game.pieces[game.getPiece("king", color)].square.y;

		for(var i = 0; i < game.pieces.length; i++) {
			pieceCheck = game.pieces[i];
			if (pieceCheck.color != color && pieceCheck.square != null) {
				fromX = pieceCheck.square.x;
				fromY = pieceCheck.square.y;
				conSq = eval("this." + pieceCheck.name + "(\"" + fromX + "\", " + fromY + ", \"" + pieceCheck.color + "\")");
				if (isin(kingX + kingY, conSq)) {
					checking = false;
					return true;
				}
			}
		}
		checking = false;
		return false;
	}


}