I won't be able to reply in one solid post, but I did some searching which led to an older thread if you want to also check that out: https://www.chess.com/forum/view/chess-openings/good-reply-for-black-to-the-london-system
I have also heard of "anti-London" system openings, but I'm not familiar what they entail. Could be a possible thing to look into as well.
Hopefully these will give some ideas in addition to any other comments. Thanks the post helped!
Instead of Nfd7 (which does look fully playable, of course) why not Nc6, meeting d5 (attacking the Knight) with e5 (attacking the Bishop) and if Bg5 then Ne7?
I will try that
I would advise the line: 1 d4 Nf6/d5 2 Bf4 Nf6/d5 3 e3 c5 4 c3 Nc6 5 Nd2 (if Nf3? Qb6 Qb3 c5 Qc2 Bf5 is possible) Bf5. Black has equalized and there’s not much to be afraid of in the line.
This is the type of line that I was look for 
Try systems with 1...c5 after 1.d4 and this can be a solid response. If you learn the theory, this can take many London players (like me) out of their comfort zones, so you should give it a try.
This is a good idea. The problem with the London opening is that it is passive and puts little pressure on Black, so they have freedom to choose their defense and there is a lot of theory to select from. The main options are probably 1...d5 and 1...Nf6. Yeah, I know - that is just one move, but there is a ton of theory and lines available. Personally, I typically play 1. d4 d5 (unafraid of the London Opening) and play for an early ...c5 with Queenside counterplay ideas.
A friend of mine in an OTB chess club played the Englund Gambit against a renowned London player - just because he wanted to get them out of book lol - He won with the Englund Gambit decisively, just because the London player was unprepared.
Maybe this is just because I am a 1500, but I am actually able to get some positional advantages + even attacking opportunities when I play the London myself. Most of these attacks stem from my opponent trying to exchange dark squared bishops. After I move the bishop back to b6, they sometimes capture it, and I capture back with my a pawn which gives my rook and open file
My recommendation try to go for this against the London system if this move order doesn't work try to eventually play c5 to make whites structure worse and force an isolated e or d pawn.
1. d4 Nf6 2. Bf4 d5 3. e3 e6 4. Nf3
Something like this could be played...
Or
Something like this could also be played
The point is the possiblities are endless, there is no point to sticking to a specific line unless you are great with it and it perfectly fits your style. Having a good broad understanding of the London System is better than knowing some specific "theory" for it.
I think anyone that play the London would have more of a feel for the opening, rather than a need to do book moves or play so mainlined, yeah sure you may memorize 3-4 moves of the opening, but more of postitional understanding takes place, rather than just books moves from what master's think or have reviewed.
Play your game and you will be fine my fellow memeber, you can trust me on this one, even I don't study opening theory as I don't have the time nor neccessity to, just play your game!
I heard that the semi-slav structure is good against the london but never tried it. Personally I play an early c5 and Qb6.
@SNUDOO
Reminds me of a runned down french, but if it works it works, what can I say?
I guess the reason this is good because you have flexibility with your light-squared bishop, but are you sure the position would be favourable for the OP?
Just making sure that's all, no offense...
Something like this could be played...
Or
Something like this could also be played
The point is the possiblities are endless, there is no point to sticking to a specific line unless you are great with it and it perfectly fits your style. Having a good broad understanding of the London System is better than knowing some specific "theory" for it.
I think anyone that play the London would have more of a feel for the opening, rather than a need to do book moves or play so mainlined, yeah sure you may memorize 3-4 moves of the opening, but more of postitional understanding takes place, rather than just books moves from what master's think or have reviewed.
Play your game and you will be fine my fellow memeber, you can trust me on this one, even I don't study opening theory as I don't have the time nor neccessity to, just play your game!
Thanks for the ideas. I guess the main takeaway is to simply keep on playing against it, and from there, decide what I like best.
Your welcome my friend...
The London System can be tricky at first, but the more you play against it the more comfortable you will fill with playing against it, and too if you play against it more you can also be effective playing with it!
Keep it up, the more you ask the more you learn...
if you want to keep it as complicated as possible, then you should go for the d6 g6 lines with an eventual c5 or e5, or the dutch with d6 and eventually e5 if allowed. the main point is not to allow a white piece to sit on e5. the drawback is that it is rather difficult to play, and especially if your repertoire vs d4 openings in general doesn't involve the kingside fianchetto or the dutch, then you have more work. d5 lines are easier to play and learn but more difficult to create problems for white in general, especially if white just wants equality he usually just gets it.
London system? White just throws away opening initiative and grovels for equality. A lazy players line. QG or KIA are better.
How do I combat super solid variations of the London System? I will post a picture of what I mean in the next post. The London System seems to be an opening which provides attacking opportunities for white if it is improperly treated by the opposing side, but for black, there seems to be no way to get a tiny advantage. I realized this today when I lost against a 1000 in blitz after he crushed me with the system. Is the only way to deal with the London System as black by trying to squeeze out an equal endgame little by little? It would also help if you would share some games which feature the London system and how the pros deal with it.
you need to strike in the center on the dark squares, and try to put a knight on e4. white's idea is to have a nice sturdy center, so trading light squared bishops is good too since that would reveal lots of light squared weaknesses.
Many setups are good against the London system. Black can play a Grunfeld or KID setup and aim for e5. Or, Nf6-d5-c5-Nc6-Bf5-e6 (or e6 without Bf5) are good.
Try systems with 1...c5 after 1.d4 and this can be a solid response. If you learn the theory, this can take many London players (like me) out of their comfort zones, so you should give it a try.
This is a good idea. The problem with the London opening is that it is passive and puts little pressure on Black, so they have freedom to choose their defense and there is a lot of theory to select from. The main options are probably 1...d5 and 1...Nf6. Yeah, I know - that is just one move, but there is a ton of theory and lines available. Personally, I typically play 1. d4 d5 (unafraid of the London Opening) and play for an early ...c5 with Queenside counterplay ideas.
A friend of mine in an OTB chess club played the Englund Gambit against a renowned London player - just because he wanted to get them out of book lol - He won with the Englund Gambit decisively, just because the London player was unprepared.
It will work at a certain level. But against a prepared opponent, and against the Englund, that is not too hard to prepare - black is just down a pawn for not much compensation.
White just has to be aware not to play 4.Bf4 which is about the only sucker trap in the Englund.
Keeping the pawn seems too materialistic too me. Why Nb4? Black can go Qb4+ Nbd2 Nge7. 4...Nc3 Nxe5 Nd5 Nxf3+ gxf3 Qd8 e4 is a good line for White
Cool trap but I play 10 minute blitz so people normally dont premove unless they are in time trouble. However, most people are probably unaware of it and would fall for it (I would)
Chessexplained has a video series on how to combat the London system. Part 1