In chess the fianchetto (Italian "little flanking") 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. In Italian, fianchetto is pronounced with a hard k sound as in "cat", but many English-speaking chess players mispronounce this word with a ch sound as in "church".
The fianchetto is a staple of many "hypermodern" openings, whose philosophy is to relinquish pawn control of the center in the hope of later undermining the opponentīs overextended pawn structure. It also regularly occurs in the so-called "Indian" defences, since fianchettoing was the standard practice in chess as it was played in ancient India, presumably because the bishop was of limited mobility and pawns were not allowed to move more than one square forward on the first move.
The diagram to the right shows two different sorts of fianchetto—a regular and long fianchetto. The movement of the bishop to the rook three square (as is common for Black in the French Defense and White in some variations of the Evans Gambit) is commonly referred to as an extended fianchetto. It can be used to prevent the opponent from castling or as a means of eliminating a bad bishop.
Common openings with a fianchetto include the Sicilian (dragon variation), Modern (Pirc defence), and Benoni systems.