Zukertort Opening: Sicilian Invitation
The Zukertort Opening is a chess opening defined by the move 1. Nf3. Sometimes the term "Reti Opening" is used to describe the opening move 1.Nf3, although most sources define the Réti more narrowly as the sequence 1.Nf3 d5 2.c4. According to databases like Chessgames.com, ChessBase and 365Chess, it is the third most popular of the twenty legal opening moves White has, behind only 1.e4 and 1.d4.
The move has been described by Edmar Mednis as a "perfect and flexible opening". The game can transpose into a large number of other openings which usually start with 1.e4, 1.d4, or 1.c4. In a majority of games, 1.Nf3 simply disappears into another opening. If Black is not careful, there is the risk of running unprepared into a highly theoretical opening, e.g. after 1.Nf3 c5 White can play 2.e4 leading to the mainline Sicilian Defense. Other common transpositions are to various lines of the Queen's Gambit Declined (after e.g. 1.Nf3 d5 2.d4 Nf6 3.c4) or the Catalan Opening (after e.g. 1.Nf3 Nf6 2.g3 d5 3.Bg2 e6 4.0-0 Be7 5.c4).
The main independent lines which usually start with 1.Nf3 are the Reti Opening (1.Nf3 d5 2.c4) and the King's Indian Attack (where White plays 1.Nf3, 2.g3, 3.Bg2, 4.0-0, and 5.d3, though not always in that order). By playing 1.Nf3 White has prevented Black from playing 1...e5, and many players who want to play the English Opening but avoid the reversed Sicilian lines beginning with 1.c4 e5 opt to start the game with 1.Nf3 instead.
Here is my first win in this debute.