The Najdorf Variation[1] (/ˈnaɪdɔːrf/ NY-dorf) of the Sicilian Defence is one of the most popular, reputable, and deeply studied of all chess openings.

[6] The Najdorf begins: Black's 5...a6 aims to deny the b5-square to White's knights and light-square bishop while maintaining flexible development.

The Czech chess master Karel Opočenský was among the first to combine 5...a6 with ...e5, and in an attempt to have the variation named after him, claimed to have shown it to Miguel Najdorf himself.

[11]Ironically, Najdorf would abandon the variation later when the theory developed to become very sophisticated:"Here comes some kid who's memorized the moves and he kills me.

[12] Bobby Fischer, who called the Najdorf "one of the greatest creations in chess theory", favoured the Lipnitzky/Fischer Attack (6.Bc4) for much of his career.

[11] He won numerous games with it as White, though in the following years counterattacking approaches were found for Black that led to its decline, though a modern variation (7...Nbd7) caused a resurgence and it appeared in the 1993 PCA World Championship match between Garry Kasparov and Nigel Short.

[16] He contributed both to the theory and the popularity of the variation while at his peak, finding ways to exploit the weakness of the d5-square created by the Black's move 6...e5.

[15] In the 1980s and 1990s, a number of English players (John Nunn, Nigel Short, and Murray Chandler) began using an approach previously tried against other Sicilian variations, such as the Dragon.

White threatens 8.e5, but Black has several options: Historically speaking, this was the usual reply until the mid-1960s, when the rejoinder 7.Bc4 put the move "out of business".

Four lines are then usual for Black: Introduced by Veniamin Sozin in the 1930s, this received little attention until Fischer regularly adopted it, and it was a frequent guest at the top level through the 1970s.

Some lines include: GM Daniel King recommends 6...g6 against the Amsterdam Variation, leading to a more defensive kingside pawn structure.

Introduced by Weaver Adams during the middle of the twentieth century, this odd-looking pawn move has mostly been used as a surprise weapon to combat the Najdorf.