colle system

Another issue is that it is only playable if Black plays a certain setup.

People that think they can play the Colle System as a catch-all opening have zero understanding of the opening.

The Colle has the same dependency as the Catalan. It ONLY works when Black's light-squared Bishop is behind the pawn chain and e6 is played.

Therefore:

1.d4 Nf6 2.Nf3 e6 - The Colle is fine here

1.d4 d5 2.Nf3 Nf6 3.e3 e6 - The Colle is fine here.

That's it! Otherwise, the Colle fails and Black is actually slightly better. Here's what else you would have to know to play the Colle:

1) The Dutch. After 1.d4 f5, systems with e3 just don't work. 2.Nc3, 2.Bg5, 2.c4, or 2.g3 is what you'd need to learn. 2.Bg5 does not work if they play 1...e6, and the Colle is inferior as they have not committed the Knight to f6 and so ...f5 is still possible.

2) Fianchetto Defenses. The Colle is no good here. The Bishop bites on granite, and the light-squared Bishop can still come out. You'd have to learn the London or Torre here after 1.d4 Nf6 2.Nf3 g6, and then something against the Modern Defense (1...g6), which both the London and Torre also fail here.

3) Slow Slav. In the "Anti-Colle" lines, which is 1.d4 Nf6 2.Nf3 d5 3.e3 and now 3...Bf5 or 3...Bg4 - White has no good move other than 4.c4, and after the most common move here, 4...c6, you are in the Slow Slav

So realistically, the Colle is only good for players over 1800 that are willing to put in the time to learn the other necessary openings.

No opening works as a system, contrary to popular amateur belief.

Agree with the above sentiments, but still may be a good repertoire mentioned by ThrillerFan for White

For most of 2019, that is what I played OTB as White.

1.d4 and then:

1...f5 2.Bg5

1...e6 2.e4 (French Defense)

1...d5 2.Nf3 Nf6 3.e3 Bf5/Bg4 4.c4

1...d5 2.Nf3 Nf6 3.e3 e6 4.Bd3 c5 5.b3 (Zukertort)

1...Nf6 2.Nf3 d5 (see 1...d5)

1...Nf6 2.Nf3 2...e6/2...g6 3.Bg5 (Torre Attack)

1...g6/1...d6 2.e4

See above - there is more than just anti-colle.

Fianchetto Defenses, Dutch, and even benoni setups.

There is a lot more than just the anti-colle Bishop moves.

You always have time to adapt your strategy: 1.d4 Nf6 2.Nf3 g6 3.e3 Bg7 4.c4 (not Bd3 stuff, which does not make sense) 4...0-0 5.Be2.

Now 5...d5 6.cxd5 Nxd5 7.e4 leads to a Grunfeld where Black cannot swap his knight, 5...d6 6.Nc3 leads to a reversed French KIA where the extra tempo is very useful to white, and 5...c5 (probably best) leads to either a strange Benoni with a pawn at e3 (which isn't best, but not a deal breaker), or a reversed Tarrasch QGD with an extra tempo for white.

And- last but not least- the Torre attack is a strong option against the ...g6 systems, if Black knows the ideas and does not play on autopilot.

Uhm, I mentioned the Torre Attack, so what are you trying to correct me about?

All your post does is confirms that the Colle sucks against fianchetto defenses.

Typically this is where the Colle is played. Can't comment on other options as I haven't tried it there.

Of course, nothing can work vs everything, anything is part of a repertoire and the Colle can even be a very good special purpose weapon, e.g. vs someone who plays 1. ..d5 as Black but not the Tartakower and plays 1. e4 as White, so the positions won't be super familiar to them and therefore they're more likely to err than in the QGD lines they're used to.

There are two Colles, Koltanowski and Zukertort, they're different so you need to pick one, both are fine, I'd prefer Colle-Zukertort.

Assuming the context is 1.d4 d5 universe, I'd say

+ allows you to cut down on theory, it's very playable and Black won't throw you their QGD pet line.

- it won't let you play the opening tic-tac-toe minigame, e.g. if you learn the QGD well, you can pose questions to Black, if Black knows the plans, structures and critical games well, they get equality of course. But if they don't, you could bring them into playing a position where they've wasted 1-2 tempos vs the best known defensive plan they have at hand.

Learning the QGD well will take you time however, about 2 years.

Also, in my view, you need to learn it as whole, both the exchange, Bg5, Bf4, it's a lot of plans, critical games, endgames and structures.

After that you'll keep studying it, evaluations of positions change, new plans come up, GMs bring existing plans to perfection etc.

So it depends on your goals, if you want to play sub 2k (fide) and have fun, playing only the Colle is absolutely fine.

If you want to try to build a repertoire to try to make it to master level, then the QGD is a good investment. But there too, playing the Colle on the right occasions has an advantage, it's feasible to find on your own a plan that's never been tried and throw it at your opponent in something less topical like the Colle. Doing the same in e.g. orthodox QGD is very hard in such a popular opening with so many professional GMs playing it on a daily basis.

You can always start with the Colle and gradually play both the Colle and QGD. Even Capablanca played a lot of Colles while he was developing as a player, it's a sound & good opening to play.

Thank You for Your wonderful, illustrative answers my dear chess colleagues!

If you play it on accident, then you won't know the lines. This is the problem.

I think it’s better to build some understanding of the structures, to see if you like them, and after that to see how you get them.

There are a bunch of strong players that play only systems(like london), and it’s very hard to beat them sometimes.

You should not play something you feel uncomfortable in, someone said that you should switch to QGD, I disagree. From my own experience( if it helps) i have periods for openings, some period i play Catalan, than some only trompawsky, i had period playing only d4, nf3, e3, be2...

On our level pretty much theory doesn’t matter , although i studied superhard I think i forgot almost everything.

AND colle is good against fianchetto g6, since when not in form, i play it, and often get good positions/ or playable positions.

Also depends on your style if colle suits your or not. If you prefer solid positions, with fixed pawn structures, can play equal positions experiment with colle, exchange variations of QGD and SLAV, london, stonewall system…