Fianchetto

In chess, the fianchetto (Italian: [fiaŋˈkɛtto] "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. 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.

The diagram to the right shows three different sorts of fianchetto (not as part of an actual game, but as separate examples that have been collapsed into a single chessboard). White's king's bishop is in a regular fianchetto, with the knight-pawn advanced one square and the bishop occupying the long diagonal. This is by far the most common type of fianchetto, seen in the Sicilian Dragon, Pirc Defence, Modern Defence, Modern Benoni, Grünfeld Defence and King's Indian Defence, among other openings.

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