What is "fianchetto"

chess move, 1847, Italian, diminutive of fianco "flank (attack)," from Old French flanc "hip, side" (see flank (n.)).

n. (context chess English) the development of a bishop by moving it one square to a long diagonal; specifically, a set of opening moves where a bishop is developed to the second rank of the adjacent knight file vb. (context chess English) to develop a bishop by moving it one square to a long diagonal; specifically, a set of opening moves where a bishop is developed to the second rank of the adjacent knight file

In chess the fianchetto ( "little flank") is a pattern of development wherein a bishop is developed to the second rank of the adjacent knight file, the knight pawn having been moved one or two squares forward.

The fianchetto is a staple of many " hypermodern" openings, whose philosophy is to delay direct occupation of the center with the plan of undermining and destroying the opponent's central outpost. It also regularly occurs in Indian defences. The fianchetto is less common in open games (1.e4 e5) but the king's bishop is sometimes fianchettoed by Black in the Spanish Game or by White in an uncommon variation of the Vienna Game.

One of the major benefits of the fianchetto is that it often allows the fianchettoed bishop to become more active. Because the bishop is placed on one of the two longest diagonals (either h1-a8 or a1-h8), it controls the maximum possible number of squares and can become a powerful offensive weapon. However, a fianchettoed position also presents some opportunities for the opposing player: if the fianchettoed bishop can be exchanged, the squares the bishop was formerly protecting will become weak (see hole) and can form the basis of an attack (particularly if the fianchetto was performed on the kingside). Therefore, exchanging the fianchettoed bishop should not be done lightly, especially if the enemy bishop of the same colour is still on the board.