Italian word meaning "on the flank". A move popularized by Russians, the Bishop is placed onto one of the long diagonals: the b2 or g2 squares for white, and the b7 or g7 squares for black.

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 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, so-called since fianchettoing was the standard practice in chess as it was played in ancient India. The fianchetto is not usually considered appropriate in open games. 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 a long diagonal (either h1-a8 or a1-h8), it controls a lot 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 and can form the basis of an attack (particularly if the fianchetto was performed on the king-side). Therefore, exchanging the fianchettoed bishop should not be done lightly.