Larsens Opening (A01)
Larsen's Opening (also called the Queen's Fianchetto Opening) is a chess opening starting with the move: 1. b3
It is named after the Danish grandmaster Bent Larsen. Larsen was inspired by the example of the great Latvian-Danish player and theoretician Aron Nimzowitsch (1886–1935), who often played 1.Nf3 followed by 2.b3, which is sometimes called the Nimzowitsch–Larsen Attack.
The flank opening move 1.b3 prepares to fianchetto the queen's bishop where it will help control the central squares in hypermodern fashion and put useful pressure on Black's kingside. The b2-bishop is often a source of recurring irritation for Black, who should not treat it lightly.
Although Bent Larsen was initially very successful with this opening, it suffered a setback in the 1970 USSR vs. Rest of the World match in Belgrade, in which Larsen played this opening against reigning World Champion Boris Spassky and lost in 17 moves. Larsen was also decisively defeated when playing this opening against Rosendo Balinas, Jr. at Manila in 1975.
Notably, the opening received interest from Bobby Fischer the same year, who employed 1.b3 on at least five occasions, winning all five, including games with GMs Filip and Mecking (Palma de Mallorca 1970 Interzonal), GM Tukmakov (Buenos Aires 1970), and GM Andersson (Siegen 1970).