Colle-Zukertort: 5.b3 is variation 3 of 6 in the Colle System course, a beginner opening course for White (ECO D05). It runs 21 moves and begins 1. d4 d5 2. Nf3 Nf6 3. e3 e6 4. Bd3 c5 …. Instead of c3, White plays b3 and puts the bishop on b2. The knight goes to e5 and the queen comes to f3 for a kingside attack. 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 with the queen's pawn.
1... d5 – Black meets it in the centre.
2. Nf3 – The knight develops and guards d4 and e5.
2... Nf6 – Black develops too.
3. e3 – The Colle move. It opens the f1 bishop and keeps d4 solid.
3... e6 – Black opens the way for the dark bishop.
4. Bd3 – The bishop goes to d3 and aims at h7.
4... c5 – Black hits d4 from the side.
5. b3 – The Zukertort plan. The dark bishop goes to b2 and aims down the long diagonal.
5... Nc6 – Black develops.
6. O-O – White castles first.
6... Bd6 – Black's bishop aims at h2.
7. Bb2 – The bishop takes the long diagonal.
7... O-O – Black castles.
8. Nbd2 – The knight develops and supports e4 and e5.
8... b6 – Black prepares to bring the light bishop to b7.
The lesson goes on for 5 more moves, each with its explanation.
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