Engine-assisted game vs Stockfish, move 4 discussion

MooMoo2 · 2016-09-25, 17:56

The most popular move on the move 3 discussion thread was ...cxd4. Stockfish played 4. Nxd4, and the FEN is:
rnbqkbnr/pp1p1ppp/4p3/8/3NP3/8/PPP2PPP/RNBQKB1R b KQkq - 0 4

Game so far: 1.e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4

Depth: 48 ply. Nodes searched: 1,336,079,061,575 (~1336 G)

WMHalsdorf · 2016-09-26, 23:18

Most likly to be played.
4...Nc6 5.Nc3 Nf6
4...Nf6 5.Nc3 Nc6

unconnected · 2016-09-26, 23:56

4...a6

LaurV · 2016-09-27, 14:26

I think that 4..Nf6 is the best continuation. Classic version.

I think a6 is weak (yeah, I know is one of the most played, and I am not an opening guru, so I can be totally wrong), its goal may be to forbid the white horse or bishop to move to b5, and/or to develop the queen's flank by moving the b pawn (maybe to b5). But in the same time it blocks both the moving of the black's horse or bishop to a6 themselves (now I talk like Raman, and yes, I know that everybody is king, with the opening book in front of him, hehe), and I think that a6 move is better to be done after white moves the horse/bishop to b5. Scary him away and keep the sente.

Also, Nc6 is a very good continuation in a face-to face play, and when you play for a draw. Here white can go for a draw easy by changing the horses, Nxc6, and we must take bxc6 (taking with d pawn is bad, he exchanges the queens and destroy our castling, we have no chance to win from there, and we have to be very lucky to get even a draw!). Therefore, 4..Nc6 5.Nxc6, bxc6, Nc3, white develops faster and we exchanged a horse and played forced moves - both these things are good recipes for a draw. Of course, white does not want draw, and he can play better than 5.Nxc6, but our goal is to win here, not to get a draw. All or nothing.

I mean, to cancel white's starting advantage, we have to play aggressively, take the lead (sente, as in go) and force him to defend (i.e. play forced moves), and we must exchange as few pieces as possible. Keep in mind that every wood we change is a little closer to the draw.

Therefore, 4...Nf6 puts pressure on the central white pawn, forced him to 5. Nc3, and then we can chose from (a) Bb4 (which puts even more pressure on the central pawn, because after we exchange the B for N, the central pawn is not defended and we take it for free), or (b) Nc6 (if he exchange, we open the column for the rook, etc), but we chose, and make him play forced moves.

The best line in the opening book may be like 4...Nf6 5.Nc3 Nc6 6. Nxc6 (or Ndb5, or a3). From here we will see... maybe start the engine... :)

LaurV · 2016-09-27, 14:55

Searching the web for former SF games, interesting that here he played white sicilian with 3.c3 (ha?) and got a draw against komodo (I assume both SF and komodo were quite old versions). Excellent game to replay! There are more SF games there, but not many sicilian.

WMHalsdorf · 2016-09-28, 14:14

Based on aggression I would rank the moves mentioned as follows (most to least)
4...Nf6
4...Nc6
4...a6

2016-09-25, 17:56	#1
MooMoo2 Aug 2010 2×7×43 Posts	Engine-assisted game vs Stockfish, move 4 discussion The most popular move on the move 3 discussion thread was ...cxd4. Stockfish played 4. Nxd4, and the FEN is: rnbqkbnr/pp1p1ppp/4p3/8/3NP3/8/PPP2PPP/RNBQKB1R b KQkq - 0 4 Game so far: 1.e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Depth: 48 ply. Nodes searched: 1,336,079,061,575 (~1336 G) Attached Thumbnails

2016-09-27, 14:26	#4
LaurV Romulan Interpreter Jun 2011 Thailand 3·17·179 Posts	I think that 4..Nf6 is the best continuation. Classic version. I think a6 is weak (yeah, I know is one of the most played, and I am not an opening guru, so I can be totally wrong), its goal may be to forbid the white horse or bishop to move to b5, and/or to develop the queen's flank by moving the b pawn (maybe to b5). But in the same time it blocks both the moving of the black's horse or bishop to a6 themselves (now I talk like Raman, and yes, I know that everybody is king, with the opening book in front of him, hehe), and I think that a6 move is better to be done after white moves the horse/bishop to b5. Scary him away and keep the sente. Also, Nc6 is a very good continuation in a face-to face play, and when you play for a draw. Here white can go for a draw easy by changing the horses, Nxc6, and we must take bxc6 (taking with d pawn is bad, he exchanges the queens and destroy our castling, we have no chance to win from there, and we have to be very lucky to get even a draw!). Therefore, 4..Nc6 5.Nxc6, bxc6, Nc3, white develops faster and we exchanged a horse and played forced moves - both these things are good recipes for a draw. Of course, white does not want draw, and he can play better than 5.Nxc6, but our goal is to win here, not to get a draw. All or nothing. I mean, to cancel white's starting advantage, we have to play aggressively, take the lead (sente, as in go) and force him to defend (i.e. play forced moves), and we must exchange as few pieces as possible. Keep in mind that every wood we change is a little closer to the draw. Therefore, 4...Nf6 puts pressure on the central white pawn, forced him to 5. Nc3, and then we can chose from (a) Bb4 (which puts even more pressure on the central pawn, because after we exchange the B for N, the central pawn is not defended and we take it for free), or (b) Nc6 (if he exchange, we open the column for the rook, etc), but we chose, and make him play forced moves. The best line in the opening book may be like 4...Nf6 5.Nc3 Nc6 6. Nxc6 (or Ndb5, or a3). From here we will see... maybe start the engine... :) Last fiddled with by LaurV on 2016-09-27 at 14:34 Reason: s/a5/a6/

2016-09-27, 14:55	#5
LaurV Romulan Interpreter Jun 2011 Thailand 21651₈ Posts	Searching the web for former SF games, interesting that here he played white sicilian with 3.c3 (ha?) and got a draw against komodo (I assume both SF and komodo were quite old versions). Excellent game to replay! There are more SF games there, but not many sicilian. Last fiddled with by LaurV on 2016-09-27 at 14:55

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2016-09-26, 23:18	#2
WMHalsdorf Feb 2005 Bristol, CT 3³×19 Posts	Most likly to be played. 4...Nc6 5.Nc3 Nf6 4...Nf6 5.Nc3 Nc6

2016-09-26, 23:56	#3
unconnected May 2009 Russia, Moscow 7·19² Posts	4...a6

2016-09-28, 14:14	#6
WMHalsdorf Feb 2005 Bristol, CT 513₁₀ Posts	Based on aggression I would rank the moves mentioned as follows (most to least) 4...Nf6 4...Nc6 4...a6