What Is a Fianchetto?
A fianchetto (Italian for "little flank") is a chess strategy where you develop a bishop to b2/g2 (White) or b7/g7 (Black) by advancing the adjacent pawn one square. The bishop then controls the longest diagonal on the board. It is a cornerstone of modern chess.
How to fianchetto
The steps are simple: advance the b-pawn or g-pawn one square (b3/g3 or b6/g6), then develop the bishop to the vacated square (Bb2/Bg2 or Bb7/Bg7). The bishop now commands the long diagonal.
Why it is strong
The fianchetto bishop is strong because: it is safe (protected by the pawn structure), it controls a long diagonal (reaching across the entire board), and it supports both attack and defence. The bishop on g2 is particularly effective at protecting the king after kingside castling.
Openings that use it
Major openings featuring fianchettos: King's Indian Defense (opening page) (g6/Bg7 for Black), Grünfeld Defence (g6/Bg7), Catalan Opening (g3/Bg2 for White), English Opening (g3/Bg2), Sicilian Dragon (g6/Bg7). See our opening encyclopedia.
Weaknesses
The fianchetto weakens the squares around it (particularly h3/h6 in front of the fianchetto). If the fianchetto bishop is traded, the remaining pawn structure can be permanently weak. This is why exchanging the fianchetto bishop is such an important strategic decision.