Openings · B90–B99

Sicilian, Najdorf

5…a6 — a move that develops nothing, and the most heavily analysed move in chess.

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6played as Black

Play it through on the board below.

Practise the line

You play Black; the other side answers on its own. Nothing here is saved or graded.

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h8
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a
Your move 1 of 50/5
  1. 1.e4c5
  2. 2.Nf3d6
  3. 3.d4cxd4
  4. 4.Nxd4Nf6
  5. 5.Nc3a6

White is answering…

The idea

…a6 takes b5 away from both White knights and the bishop, which is what makes …e5 possible later: the pawn on e5 leaves a hole on d5, and the hole is only survivable when the b5 square is covered too.

It also prepares …b5, the queenside expansion that is Black's counterplay in nearly every line. What it does not do is develop a piece, and that is the bargain — the sharpest position in chess, on the understanding that both players know it.

Common mistakes

Three that come up again and again below master level: named traps and the errors every coach corrects.

Playing …e5 against the pin

After 7.Nf5
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
The mistake
Answering 6.Bg5 with 6…e5, the way …e5 answers almost everything else.
Why it costs
Normally …e5 kicks the knight to b3 and gains a move. Here the knight goes forward to f5 instead, where it eyes d6 and g7, and the natural …g6 to chase it costs the dark squares with a bishop already pinning the knight on f6.
Instead
6…e6, which is the main road — including the Poisoned Pawn, if that is a road you have walked before — or 6…Nbd7. Save …e5 for the sixth moves that leave the knight nowhere to go but b3.

Castling into the English Attack

After 10.O-O-O
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
  8. 8.
  9. 9.
  10. 10.
The mistake
Castling short against Be3, f3 and Qd2 before the queenside counterplay has started.
Why it costs
Opposite-side castling is a race, and White's runner — the h-pawn, behind g4 — is already moving. Black's is …b5, …Nbd7–b6 and …Rc8, and none of it has begun. A move spent on the king here is a move the attack gets for free.
Instead
…Nbd7 and …b5 first, and castle when the race is on. Strong Najdorf players often leave the king in the centre for a long time, and sometimes it never castles at all.

One answer for eight sixth moves

After 6…e5
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
The mistake
Learning a single set of moves and playing it whatever White does on move six.
Why it costs
6.Bg5, 6.Be3, 6.Bc4, 6.h3, 6.f4, 6.Be2, 6.a4 and 6.g3 are eight different openings, not eight move orders. Against 6.Bc4 the reply 6…e5 is met by 7.Nde2, and the …Be6 that normally follows is an invitation to double the pawns instead.
Instead
Pick one answer to each, and write them down. If that sounds like too much work, the Kan and the Classical ask far less of your memory for a very similar kind of game.

What the engine says

After 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6, these are White's six best moves according to Stockfish, with the bar showing White's chance of winning. The whole list sits within 1 percentage point of win chance: none of them is a mistake, and the choice is about the positions you want to play.

  1. Be3+0.5
  2. Be2+0.4
  3. Nb3+0.4
  4. Qd3+0.4
  5. f3+0.4
  6. Bg5+0.4

The engine's main line from Be3: Be3 e5 Nb3 Be6 h3 Nbd7 g4 h6.

Stockfish 18, depth 24. Scores are in pawns from White's side. Another engine or depth will move individual numbers a little; the picture does not change. How we check.

Where it fits

The Sicilian, Najdorf is a variation of the Sicilian Defence, whose page covers the ideas this one takes for granted.

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