Benko's Opening, also known as the King's Fianchetto Opening, the Hungarian Opening, or the Rat Opening, is an irregular chess opening defined by the move 1.g3. ECO code: A00.

History

The opening is named after Pal Benko (1928–2019), the Hungarian-American grandmaster who employed it extensively at the 1962 Candidates Tournament in Curaçao, using it the first eleven times he had the white pieces—defeating both Bobby Fischer and Mikhail Tal. Indian players had employed the move as early as 1828, as noted in Ghulam Kassim's annotations from Madras. The hypermodernist Richard Réti also played it at Baden-Baden in 1925. Viktor Korchnoi later used it against Anatoly Karpov in the 1978 World Championship.

Main Lines & Variations

White prepares to fianchetto the king's bishop to g2, controlling the long h1–a8 diagonal. As opening expert Nick de Firmian has noted, the move "can, and usually does, transpose into almost any other opening in which White fianchettos his king's bishop." Common transpositions include:

• The King's Indian Attack (via Nf3, d3, Bg2, 0-0, e4)

• The Catalan Opening (via d4, c4, g3, Bg2)

• The English Opening (via c4, g3, Bg2)

• The Réti Opening (via Nf3, g3, Bg2)

Strategic Themes & Plans

The opening generally leads to closed or semi-closed positions where White delays committing to a specific central pawn structure. White's bishop on g2 exerts latent pressure on the centre and queenside. The fifth most popular opening move, it is nonetheless far less common than 1.e4, 1.d4, 1.c4, and 1.Nf3. It should not be confused with the Benko Gambit (1.d4 Nf6 2.c4 c5 3.d5 b5), which is an entirely different opening.