fianchetto

Fianchetto is a chess term describing a bishop development pattern in which the bishop is placed on b2 or g2 for White, or on b7 or g7 for Black, behind a pawn that has been advanced to g3 (or b3) for White, or to g6 (or b6) for Black. The term is of Italian origin, from fianco meaning flank; fianchetto roughly translates as “little flank.” The arrangement gives the bishop a long-range diagonal toward the center and can support central and queen-side operations while keeping the bishop relatively safe.

Common manifestations include White fianchettoing the kingside with g3 and Bg2, or the queenside with b3 and Bb2; Black fianchettoes with g6/Bg7 or b6/Bb7. This feature is central to hypermodern openings, and is a hallmark of systems such as the Catalan, certain English/Reti setups, and the King's Indian Defense (and the King's Indian Attack when White opts for g3 and Bg2).

Strategic ideas: The fianchetto bishop exerts pressure along the long diagonal, often supporting a flexible center and rapid development. It can increase king safety in closed centers and provide a powerful diagonal in open positions. It also allows White to avoid blocking c- and d-pawns. Risks include potential weakening of the base of the pawn chain and dependence on a single long diagonal; if the center breaks with d5 or e5 or if the diagonal is challenged, the bishop can become a tactical target.

Variations such as the double fianchetto place both bishops on b2 and g2 (or b7 and g7), creating a very solid but sometimes slower setup.