Main line: 5.a4 Bf5 6.e3 is variation 1 of 6 in the Slav Defence course, a intermediate opening course for Black (ECO D18). It runs 26 moves and begins 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 …. Black takes on c4, White plays a4 to stop ...b5, and Black develops the bishop to f5 before playing ...e6. After ...Bb4 and ...O-O, White pushes e4-e5 and Black settles a knight on d5. In the lesson every move is explained on a board and then drilled; it is free.
Move by move
1. d4 – White takes the centre.
1... d5 – Black claims an equal share of the centre.
2. c4 – The Queen's Gambit, attacking d5.
2... c6 – The Slav: d5 is supported by a pawn, and the c8 bishop is not blocked as it would be after ...e6.
3. Nf3 – Develops and covers e5; it also keeps White's options open against ...dxc4.
3... Nf6 – Develops and attacks e4.
4. Nc3 – Adds a second attacker to d5 and prepares e4.
4... dxc4 – Now that White's knight has left b1, Black grabs c4 and gains time; the c6 pawn means ...b5 can hold it for a while.
5. a4 – Stops ...b5 so the pawn on c4 can be won back without trouble.
5... Bf5 – The key Slav move: the bishop leaves before ...e6 and controls e4.
6. e3 – Prepares Bxc4, winning the pawn back with easy development.
6... e6 – Now ...e6 is right: the f5 bishop is already outside the chain and the f8 bishop is freed.
7. Bxc4 – White regains the pawn and develops.
7... Bb4 – Pins the c3 knight and slows down e3-e4.
8. O-O – White castles.
8... O-O – Black castles too.
The lesson goes on for 10 more moves, each with its explanation.
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