In Flexible Chess (F-chess) the rules are the same as in orthodox chess except that knights and bishops are initially placed outside the board. Any empty square on the first rank can serve as initial square, creating great opening flexibility without departing from standard opening strategy. Bishops and knights can be introduced via any empty square on the first rank and move immediately, effectively a double-move. Pieces can be introduced at any time, provided that a move exists that originates from the first rank. For instance, if the white queen has already moved away, a knight can be introduced via d1, thus reaching the square b2 (provided that it is empty). The bishops must be inserted on different colour squares. Flexible Chess is intended as an alternative to standard chess, radically increasing the ramification of openings. By waiting a few moves before introducing an external piece, a player can hide his strategical intentions.