Opening prep 1.1: Colle system basics

Tips:
1. Not suitable for every situation like the London, if black deviates, white can lead to a bad situation. Improvise rather than follow strictly.

2. Critical moves: d4, Nf3, e3.

3. The traditional system features c3, Nd2, Bd3, O-O and the Zukertort system features b3, Bb2, Bd3.

4. Advantage: Doesn't have to memorise too much theory, the strategy is simple and not easy to play against.

5. Pawn breaks:e4, even e5 if possible and start a kingside attack.

Traditional system

Playing for early development, for the e4 break, similar to the semi-slav in reverse, launch a kingside attack.

After 1.d4 d5 2.Nf3 Nf6 3.e3 e6 4.Bd3 c5

white can prepare for the e4 to open the dark bishop, which is also possible through ....b3 and Bb2

After 5.c3 Nc6 6.Nd2 Bd6 if white play c4 or e4 directly will leave an iqp, and square e5 is weak for the knight.

mainline: 7. dxc Bxc 8.O-O O-O

Playing as a semi-slav

9. b4 and try to play a3, Bb2, c4, but c3 is weak

Playing straightforward

9.e4 dxe 10.Nxe

Black's light bishop is worse, and white has a queenside majority.

If white plays e5 too early black can play f6 and have a good 'French'.

Sometimes play Qe2 to strengthen the e-pawn。

Zukertort system 

5.bc Nc6 6.O-O Bd6 7.Bb2 O-O

Don't play dxc, because if Ne5 no pawn is going to kick f6 knight.

Play like a reversed stonewall with Ne5, f4

Sometimes throw in a3 to avoid Nb4 kicking the Colle bishop on d3

If white plays ...Ne5 Nxe5 lose a piece

if Bxe5 dxe5 then white continues with f4 and c4 dxc4 Nxc4 ready to hop in d6, the attack is easy

black's aim is b5 Nf5

if moves like Qc7 prevents white's Nf5 plan, white should consider c4 as a break.

Colle vs London(not recommended)

1.d4 d5 2.Nf3 Bf5 3.e3 would lead to an unfavourable situation for white

3.c4 e6 4.Nc3 c6

5.Qb3 punishing early bishop by black and play aggressively.

if 5.Qb6 6.c5 Qc7 7.Bf4(QxB than lose R) ...8.e3

it's already +1

Colle vs Grunfeld(not strong but fine)

try Re1 or b3 Bb2 if stick to the Colle

Colle vs Benoni / queen's Indian (ok but be careful)