The only Pawn moves which fit this description are moves with the King’s or Queen’s Pawns as they open lines for Queen and Bishop—­ apart from an additional square for the Knight—­while the other Pawns cannot free the way for more than one piece.  Whether the move with the King’s Pawn or the Queen’s Pawn is better when beginning the game is impossible to say.  In neither case can it be proved that White can obtain an advantage which is sufficient to win the game.  With correct play on both sides it can be only White who gains an advantage, for he has the first move and so he is one move ahead of Black in the development as long as he does not waste any time on maneuvers which do not increase the mobility of his pieces.

By the mobility of a piece is meant the number of squares accessible to it.  A Bishop or a Rook which stands in an unobstructed file is obviously worth more than one whose sphere of action is limited on account of his way being blocked.  This does not mean, however, that a Bishop or a Knight to whom, at a certain moment, three or four squares are accessible, is more valuable than a Rook who at the same moment can go only to one or two squares; for a few moves later the Rook might be in possession of his full freedom while the action of the Bishop or the Knight might be hampered.  It is, therefore, best to value the pieces according to their latent strength, that is, the strength which is likely to show in the ending after all temporary obstructions have been removed.  The comparative values given for the different men on page 42 will serve as good guide in most cases.  It is not advisable though to give up a minor piece for three Pawns or two minor pieces for a Rook and one Pawn as long as Queens and minor pieces are on the board, as with a piece ahead the opponent mostly succeeds in winning through a direct attack against the King before the superiority of Pawns becomes dangerous.

In trying to place the pieces on squares where they have as much mobility as possible individual thought is required with each new game as it depends altogether upon the moves of the opponent which lines can be opened for Bishops, Rooks and Queen and where a good field of action can be secured for the Knights.  However, it is possible to give a few rules which common sense tells us must hold good in the majority of games if both players play well.  Of course, if a player makes bad moves in the opening, that is, moves which do not aim at a speedy mobilization of all pieces, then the opponent may soon have a chance to win the game with moves which are not in accordance with those common sense rules either but which force an immediate issue in a maneuver of a kind that ordinarily does not occur in an opening but is characteristic of the middle game.  This is a point which the majority of Chess players overlook.  They argue that—­granted the value of general principles of strategy, which will greatly help to build up a safe position—­cases occur in which a move may win which is not according to principles, and that, therefore, following the trend of a certain combination which seems profitable, is advisable even if the general principles are violated.