Main variation with 3.Nc3
Caro-Kann - Classical main variation with 4...Bf6:
1. e2-e4 c7-c6 2. d2-d4 d7-d5 3. Nb1-c3 White develops a knight and protects the pawn on e4.
3...dxe4 Black takes the e4-pawn and prepares to develop his light-squared bishop to f5.
4. Nxe4 Bc8-f5 White had to recapture on e4 and Black continues with the development of the bishop to f5.
5. Ne4-g3 The knight was attacked and had to move. With his retreat to g3 White gains time because he is attacking the bishop on f5.
5...Bf5-g6 Black moves his bishop back.
6. h2-h4 An interesting move. Before continuing to develop White sets up the threat of h4-h5 after which the black bishop on g6 would be lost.
6...h7-h6 Black creates a retreat square for the bishop on g6.
7. Ng1-f3 White develops the second knight.
7...Nb8-d7 Black develops a knight and controls the e5-square, also so as to stop the white knight from quickly occupying it.
8. h4-h5 White attacks the bishop and gains space on the kingside.
8...Bg6-h7 There was no alternative to this move.
9. Bf1-d3 White continues like this (in principle without exception) in order to swap off Black’s strong bishop.
9...Bxd3 10.Qxd3 After the exchange of bishops we have reached the basic position for this variation. White is planning to bring his dark-squared bishop into play and to castle long in order to attack on the kingside as soon as Black has castled short, Black usually castles short. So he must first bring his kingside pieces into the game and that is his next goal.
Caro-Kann - main variation with 4...Nd7:
Black prepares the developing move 5...Ng8-f6 which at the same time offers the relieving exchange of the knight on e4. This system was frequently played by World Champion Karpov. For Black knowledge of the sharp variations with 5.Ng5 is vital
Caro-Kann - main variation with 4...Nf6:
Black goes full out on the kingside without worrying about a pretty pawn structure. White now takes the knight. If Black recaptures with the g-pawn that opens the g-file as a line along which to attack the white king, which leads to sharp positions. That, however, produces a shattered pawn structure which will be very vulnerable in the endgame. A quieter move is to retake with the e-pawn which leads to more comfortable development for Black.
The Advance Variation with 3.e5
Caro-Kann Advance Variation:
1. e2-e4 c7-c6 2. d2-d4 White accepts the opportunity and occupies the centre with a second pawn.
2...d7-d5 Black continues his plan and attacks the e4-pawn. White must now react to this threat.
3. e4-e5 The Advance Variation. White protects his pawn by advancing it. In addition he seizes space in the centre which is now closed.
3...Bc8-f5 Black develops his light-squared bishop. It is important to do so instead of shutting it in with …e7-e6. This is one of the main ideas of the Caro-Kann Defence.
4. Ng1-f3 White develops his knight.
4...e7-e6 Black makes room for the other pieces.
5. Bf1-e2 White continues his development and prepares to castle kingside. He has a lead in development, but, since the position in the centre is closed, that hardly matters. Black can handle the position flexibly. He can immediately attack the white centre with …c7-c5 or first bring his knights into play via e7 and d7 and slowly but surely aim to castle short. White will go on to castle and bring his queenside pieces into play.
Exchange Variation and Panov Attack 3.exd5
Panov Attack :
1. e2-e4 c7-c6 2. d2-d4 d7-d5 3. exd5 White can also solve the problem of the threat to his pawn by simply exchanging on d5 himself.
3...cxd5 Black recaptures with the pawn. As a rule that is the correct reaction, in order to have a pawn placed in the centre.
4. c2-c4 This introduces the Panov Attack. White attacks the pawn on d5 and hopes for rapid development. It would, for example, be a mistake for Black to take on c4 and allow White the rapid development of his light-squared bishop.
4...Ng8-f6 Black protects the pawn with his knight, which he brings into play at the same time.
5. Nb1-c3 White develops the knight and obtains pressure against the d5-pawn. Here Black has several possibilities. He can continue with …e7-e6 and push on with the development of the kingside; he can continue with …Nb8-c6 and keep open the possibility of quickly bringing the light-squared bishop into the game; but he can also play …g7-g6 intending to develop the dark-squared bishop to g7. White proceeds accordingly, but as a rule he develops his kingside pieces quickly and castles short.
The Exchange Variation:
1. e2-e4 c7-c6 2. d2-d4 d7-d5 3. exd5 cxd5 4. Bf1-d3 this setup tends to be of a more peaceful nature and at first does not initiate any contact with the opposing forces. White exchanges on d5 and develops his light-squared bishop to d3. The idea is to make it hard for Black to bring his light-squared bishop into the game.
4...Nb8-c6 Black develops a knight and attacks the d4-pawn.
5. c2-c3 White protects the pawn on d4.
5...Ng8-f6 Black develops the second knight and prepares the development of his light-squared bishop to g4. White will now bring his dark-squared bishop into play and after that always his queen‘s knight first before developing the other knight to f3. As soon as Black has developed his bishop to g4 White puts his queen on b3. When Black has his light-squared bishop in play he deals with the development of his kingside.