Sicilian question

The last position is imo still in the Sicilian general theme. The Najdorf in particular is an improved "wait and see" variation. So I will start with discussing the general Sicilian ideas then discuss the position in question (but will not discuss the philosophy behind first 6 moves)...

(1) Black has a weak d6-pawn or loss of control against d5 square. White will add pressure on d6-pawn, or add control against d5 square so the d6-pawn cannot advance. Thematic moves are Qd2/Qd3, Rd1/0-0-0, Bc4-Bb3, Nd5. Black will try to guard the d6-pawn and to control d5 square so the pawn can be pushed. Black's thematic moves to control d5 are ...Be6/Bb7, ...Nbd7-Nb6, ...Qc7, ...Rd8, Be7 (instead of Bg7). This usually can be done by exchanging pieces.

(2) If White is a good attacking player he may want to attack the kingside with the advantage he has in tempo (pioneered by pawn advancement such as f4 or f3-g4). Black will counter attack on the queenside with thematic moves such as ...Qc7 (to control the open file, defend e5 and empty d8 for the rook when needed to defend d6-pawn) and ...b5.

Now let me analyze what Black has to do in the last position after 7.Nf3...

(1) White's 7.Nf3 blocked the f-pawn, meaning that White doesn't show his intention to launch a quick kingside attack. If White's intention is to play positionally with small advantage in the queenside, the battle for d5 square will become more critical.

Black may want to prepare ...Nd7-Nb6 to control d5 square, but this should be done carefully because ...Nd7 blocks d6-pawn from its defender on d8 and blocks the bishop in case ...Be6 is required, and ...Nb6 interfere with ...b5. The ...b5 will weaken the queenside (where White may challenge with a4) but is required in case of counterattack. If White has not shown his intention to attack the kingside, Black should refrain from ...b5.

Another option for the knight is ...Nc6. This will not control d5 square directly but is usefull to attack White's Bc4-Bb3 when followed with ...Na5 (and then ...Nc4 to attack Be3).

So the queenside-knight development (...Nbd7/Nc6) can/should wait.

(2) Queenside bishop development to b7 (e.g. 7...b6-Bb7) to control d5-square is too slow and thus dangerous because White's Bc4 should be countered with ...Be6. OTOH, immediate 7...Be6 will be challenged by 8.Ng5. You have to prepare your own line here if you want to take advantage from this "unknown" (difficult for Black) structure. So 7...Be6 is playable with caveat.

(3) If you plan to control d5 square with ...Be6 and don't like Ng5 attack then you need to protect g5 square with preliminary 7...h6 move where the tempo spent for that move can be used by White to proceed with Bc4. I think this is equivalent with previous plan (7...Be6)

(4) 7...Bg4 is wrong (it might be just risky like many other Sicilian lines, but if you're not prepared with the consequences I would say it is wrong) because Black will lose many tempo to retreat the bishop after 8.h3 (Black of course will not exchange the bishop for a knight plus free development of White's queen).

This loss of tempo can be used by White to win more tempo by advancing/attacking the kingside so that 8.h3 is more an advantage than a weakening move.

(5) 6...Ng5 is my pet line in the Najdorf. This move (7...Ng5) cannot be done on the 7th move after 6...e5 because Black's Queen now is exposed to 7.Bg5 attack and 7...f6 is not possible (to attack the bishop) because it will destroy Black's King only shelter (e.g. the exposed a2-g8 diagonal)

(6) Black's plan for 0-0-0 in any stage of the game is almost impossible. With his own pawn on e5 and the need to defend d6-pawn, the kingside bishop will for sure have to go to e7, not g7. And this (7...Be7) is the only move that is not flexible in nature, so should be prioritized. Only 7...Qc7 that is comparable in term of inflexibility, but ...Qc7 is more a counterattack maneuver than piece development, so Black may become "less" developed if White decides to play for the queenside.

CONCLUSION:

7...Be7 is imo the theoretical "best move", because it is in line with the "wait and see" spirit of the Najdorf. But like in any other Sicilian lines, inferior moves are still playable due to the complex structure of the Sicilian.

Thanks for the detailed response.