Chess Opening Theory/1. e4/1...c5/2. Nf3/2...Nc6/3. c3
Sicilian Defense Alapin Variation 2.. Nc6 3.Nf3Edit
The Opening Line 1.e4 e5 2.Nf3 Nc6 can transform from the Old Sicilian to the Alapin variation with 3.c3. The ideas of this line are the same as the regular Alapin. The most common responses are 3... Nf6, 3... d5,and 3... e6. Other moves that can be played, but are less common are 3... e5, 3...d6, 3...Qa5, and 3...g6.
The common responses to 3.c3 are 3... Nf6, 3... d5 and 3... e6.
The Ideas behind this move is to develop blacks king knight, and strike at whites e4 pawn. Common replies to this move are 4. e5 attacking blacks knight and forcing it to move. The most common and best square to lace the knight is d5 with the move 4... Nd5. The knight on this square is now only subject to attack from the c4 pawn where if 5. c4 black can play the knight to b6. gaining an attack on the d pawn and still controlling d5. Other replies to Nf6 are 4. e5 where black is fine after taking on e4 or slightly worse is playing 4... d6. Other replies to 3... Nf6 are d3, where black can reply with e6 opening the diagonal for the dark square bishop and preparing for an eventual strike on the center by playing d5 supported now by the e pawn, the king knight, and queen.
This move provokes the center and black demonstrates their wish to control the game. The move 3.d5 seeks to undermine the white pawn on e4 by trading it with blacks d pawn. It also seeks to bring the queen out to the center where black has chances to build huge center control. The move of 3. c3 prevents whites knight from coming out and attacking the queen, making it harder to expel the black queen from the center. Common replies to 3... d5 are 4.exd5 where black response has to be 4...Qxd5 to keep material even. White has a few choices following the queen taking on d5. If white plays 5.d4 he enter the Sicilian Defense Alapin Variation, Barmen Defense. Black has many response but the best are developing a piece rather than the playable but slightly worse cxd4. Other responses to 3...d5 are d3 defending whites pawn as white seeks to maintain his stake of the center. Blacks best responses to this are playing 4...e6 as black also seeks to maintain his center. Another less common response is 4.e5, which is followed by black playing 4...e6 stopping the advancement of the e pawn and protecting his d pawn. Following this line white commonly strives to play a closed game and protect his advanced e pawn by playing move such as 5. d4 trying to trade pawns and protect the pawn on e5. Lastly white can respond to the d5 pawn push by playing 4. Bb5 pinning whites knight to his king, and developing an piece. Again blacks reply to this move should be to stop the advancement of the e pawn and protect his d pawn with the move 4... e6.
The pawn move of 3... e6 opens the diagonal for blacks bishop to protect the c5 pawn while preparing the push of d5 transposing into the same position as 3...d5 with the e5 response. Common replies to blacks 3... e6 are d4 where black responds with d5 or slightly worse taking on d54 with 4...cxd5. The move 4... d5 keeps the tension in the center giving white the choice of opening the game and losing some control of the center. Common responses to the move 4.. d5 are 5.e5 reaching the same position as the French Defense: Advanced, Paulsen Attack.