In
chess, a
fianchetto (verb: "to fianchetto") is a specific pattern of
piece development in the
opening in which one (or both) of the
bishops is moved from their starting position to the second
rank of the adjacent b or g
file (the b2 and g2 squares, respectively), that space having been vacated by moving the knight pawn that previously occupied it forward one space (or much more rarely, two spaces).
This creates the appearance of a bishop hanging out in a little tent made of three pawns, as in the following example where both black and white have fianchettoed their kingside bishops:
| ♜ |
♞ |
♝ |
♛ |
♚ |
|
♞ |
♜ |
| ♟ |
♟ |
♟ |
♟ |
♟ |
♟ |
♝ |
♟ |
| |
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|
♟ |
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♙ |
|
| ♙ |
♙ |
♙ |
♙ |
♙ |
♙ |
♗ |
♙ |
| ♖ |
♘ |
♗ |
♕ |
♔ |
|
♘ |
♖ |
Fianchettoed bishops are one of the main strategies in so-called "hypermodern" openings, which eschew direct occupation of the center in order to undermine and harass the opponent's central pieces from the wings. It is also a staple of the various Indian attack and Indian defense openings, as traditional Indian chess did not allow pawns to advance more than one square on their first move, thus making openings involving fianchettoed bishops more attractive than many other types of openings.
Fianchettoing bishops makes them immensely powerful because it gets them onto a long diagonal, often X-Raying the opponent's rook. However, it also makes them a target and if the opponent can successfully trade off their same-color bishop for the fianchettoed bishop it will generally leave a weakness (called a "hole") in the fianchettoing player's defenses.
The word fianchetto comes from Italian, meaning "little flank," and being an Italian word, is most properly pronounced "fianketto" with a hard "k" sound.