Sicilian Defense, Najdorf Variation

The Najdorf arises in the Open Sicilian Defense. White plays d4, Black's c5-pawn captures it, and a white knight recaptures on d4. Black has therefore exchanged the c-pawn for White's d-pawn and gains a semi-open c-file, a vertical line without a black pawn that can be used by the rooks. The move that defines the Najdorf is ...a6.

The move that defines the Najdorf

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Starta6

b5 is a square that White's pieces may try to use.

Before ...a6

The Open Sicilian structure is already present, but Black has not moved the a-pawn yet.

1. b5 is a square that White's pieces may try to use.

Why ...a6 matters

• The a6-pawn controls b5 and keeps a white knight or bishop from occupying that square comfortably, sometimes with check.
• It prepares a possible queenside expansion with ...b5.
• It does not yet commit the e7-pawn, which may later advance to e5 for space or to e6 for a more compact structure.

The ...e5 option

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The e5-pawn attacks the knight on d4, which must move.

More space and a sensitive square

This representative position appears after 6.Be3 e5. Black gains space but must watch d5.

1. The e5-pawn attacks the knight on d4, which must move.
2. The advance leaves d5 without protection from a black pawn.

The ...e6 option

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The e6-pawn controls d5 and can help prepare the ...d5 break.

A more compact structure

After 6.Be3 e6, Black keeps the e-pawn on a more restrained square and continues developing.

1. The e6-pawn controls d5 and can help prepare the ...d5 break.
2. Moving the e-pawn makes e7 available for the bishop to develop.

That flexibility explains both the strength and the difficulty of the variation. White can choose very different development schemes and often attacks the king, while Black seeks counterplay on the c-file, in the center, and on the queenside. The Najdorf contains extensive theory, but its basic idea is not memory for its own sake: ...a6 restricts b5 and lets Black delay the decision about the central pawns.