Answers.Body: <p>The answer is no since f3 would never be played there by any strong player as it is weakening, but has no compensating advantages.</p>
  
  <p>That is very close to some virtually-impossible-to-get-to lines in the Bishop's Opening/Vienna game since unlike the queen-pawn London, black has many more ways to throw a wrench into the attempt to play moves without thinking. In an idea world where black cooperates, in the Bishops's, white can try to play for that setup, but would  play f4, which has the advantage of attacking the black center, and opening the f-file.</p>
  
  <p>You can see from this contrived variation that black has many better options, and is not likely to just submit to white's desire to play a London on the kingside. In no case would f3 be good.</p>
  
  <pre><code>  [FEN ""]
  
   1. e4 e5 2. Bc4 Nf6 3. d3 Nc6 4. Nc3 Be7 (4... Na5 $1 {Blows up the whole idea. }) (4... Bc5 $1 5. Nge2 d6 6. O-O a6 7. Kh1 $2 Ng4 {So it is impossible to get in f4 here.}) 5. Nge2 d6 6. O-O (6. a3 $1) 6... O-O 7. f4 (7. a3 $1) 
  </code></pre>
  
  <p>.</p>
  
  <pre><code> [fen "rnbqkbnr/pppppppp/8/8/2B1P3/2NP1P2/PPP1N1PP/R1BQK2R w KQ - 0 1"]
  </code></pre>
  
  <p>.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-02-20T23:48:36.930Z
Answers.Text: f3 could be played if the plan is to castle queenside in the near future, or just do it first before f3. The normal London can often be played in various orders, and c3 usually comes pretty late, so f3 here in the mirror would hopefully come rather late too. Only real question is where to put the other Bishop. I often struggle with that when playing the London.
Answers.UserDisplayName: DrZ214
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-02-21T00:20:49.480Z
Answers.Text: In my opinion, f3 would still serve little purpose even with long castling. At best, you would want to hold off on it for as long as possible.
Answers.UserDisplayName: PhishMaster
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-02-20T23:36:32.863Z
Answers.LastActivityDate: 2020-02-21T09:53:25.653Z
Answers.LastEditDate: 2020-02-21T09:53:25.653Z
Answers.UserDisplayName: PhishMaster
Answers.Body: <p>Unaware of any special name given to that full sequence of moves, especially as a 'system' as opposed to an opening variation name.</p>
  
  <p>f3 is a major mistake and would not be played except by beginners. there is a difference between qp and kp setups so that they cannot be mirrored well like  you asked. </p>
  
  <p>Some of the previous move sequences do have a name.  It would roughly fit in the bishops opening or some others depending on what black did. </p>
  
  <p>I found some  games of 2500+ players using those moves up to f3 which is terrible bad and white won 3 of the ones I tracked in detail  based on most likely moves according to one tablebase. </p>
  
  <p>Which I suspect is that winning is more because of the unusualness than the soundness.  The position at that point is dead even and any winning came much later from other moves.</p>
  
  <p>The opening is unusual but playable although apparently not at the GM level for black which further reinforces my belief that the value comes from what happens later and depends how both sides play.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-02-20T23:49:43.973Z
Answers.Text: f3 could be played if castling queenside. See comment on PhishMaster's answer.
Answers.UserDisplayName: DrZ214
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-02-20T23:53:08.343Z
Answers.Text: true  but f3 is still bad.  as phishmaster said there are no compensating advantages.
Answers.UserDisplayName: edwina oliver
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-02-20T23:40:12.497Z
Answers.LastActivityDate: 2020-02-20T23:40:12.497Z
Answers.UserDisplayName: edwina oliver
Answers.Body: <p>A reverse London would be either a slav or a caro-kann. It's a perfectly viable idea to play although most GMs might not like it because there are some drawish lines. If that's an idea that appeals to you, you can build a very simple opening rep. There's a lot of books, most of them will refer to it as a triangle system (based on the pawn structure with e6, d5, c6- which forms a triangle)</p>
  <p>I don't understand the other answers. They seem to be focusing on specific lines rather than what the question is actually asking.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-05-11T06:48:52.673Z
Answers.Text: The question asks about a *horizontal* mirror (so it's still a White opening), not a *vertical* one.
Answers.UserDisplayName: Glorfindel
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-05-11T04:22:15.527Z
Answers.LastActivityDate: 2022-05-11T04:22:15.527Z
Answers.UserDisplayName: Savage47
Body: <p>London System is an opening for white, that goes d4, Bf4, e3, Nf3, Nd2, c3. The move order generally doesn't matter too much and there are lots of ways to transpose into this.</p>
  
  <p>However, what I want to know now, <strong>is the horizontally mirrored way also a valid system?</strong> White will play e4, Bc4, d3, Nc3, Ne2, f3.</p>
  
  <p>(Note this is not the same as the Italian Game because there, the g Knight goes to f3 instead of e2.)</p>
  
  <p>So is this a real system, and if so, what is its name? I'd like to read more about it and its theory. Is it sound? Are there way more traps white has to watch out for?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-20T23:45:55.780Z
Comments.Text: Any reason for the downvote? Something wrong with the question, or how can it be improved? Seems totally on topic and valid question to me.
Comments.UserDisplayName: DrZ214
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-20T23:52:21.640Z
Comments.Text: ^ not sure the downvote either, seems like a perfectly valid question
Comments.UserDisplayName: mowwwalker
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-21T00:22:21.173Z
Comments.Text: I agree, and upvoted you too.
Comments.UserDisplayName: PhishMaster
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-05-11T06:48:50.723Z
Comments.Text: Please note that in the London, you play c3 because you have to, not really because you want to. Since ....f5 will not be a common move for Black to play on 1.e4 openings, you will rarely need a move like f3
Comments.UserDisplayName: David
Tags: <opening><london-system>
Title: Is there a horizontally mirrored London System, and what is it called?
ThreadText: # Is there a horizontally mirrored London System, and what is it called?
  
  (Asked by: username_0 on 2020-02-20)
  
  London System is an opening for white, that goes d4, Bf4, e3, Nf3, Nd2, c3. The move order generally doesn't matter too much and there are lots of ways to transpose into this.
  
  However, what I want to know now, **is the horizontally mirrored way also a valid system?** White will play e4, Bc4, d3, Nc3, Ne2, f3.
  
  (Note this is not the same as the Italian Game because there, the g Knight goes to f3 instead of e2.)
  
  So is this a real system, and if so, what is its name? I'd like to read more about it and its theory. Is it sound? Are there way more traps white has to watch out for?
  
  **Tags:** opening, london-system
  
  > **Comments:**
  > **username_0**: Any reason for the downvote? Something wrong with the question, or how can it be improved? Seems totally on topic and valid question to me.  
  > **username_1**: ^ not sure the downvote either, seems like a perfectly valid question  
  > **username_2**: I agree, and upvoted you too.  
  > **username_3**: Please note that in the London, you play c3 because you have to, not really because you want to. Since ....f5 will not be a common move for Black to play on 1.e4 openings, you will rarely need a move like f3  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_2 on 2020-02-20. Score: 10
  
  The answer is no since f3 would never be played there by any strong player as it is weakening, but has no compensating advantages.
  
  That is very close to some virtually-impossible-to-get-to lines in the Bishop's Opening/Vienna game since unlike the queen-pawn London, black has many more ways to throw a wrench into the attempt to play moves without thinking. In an idea world where black cooperates, in the Bishops's, white can try to play for that setup, but would play f4, which has the advantage of attacking the black center, and opening the f-file.
  
  You can see from this contrived variation that black has many better options, and is not likely to just submit to white's desire to play a London on the kingside. In no case would f3 be good.
  
  ```
    [FEN ""]
  
   1. e4 e5 2. Bc4 Nf6 3. d3 Nc6 4. Nc3 Be7 (4... Na5 $1 {Blows up the whole idea. }) (4... Bc5 $1 5. Nge2 d6 6. O-O a6 7. Kh1 $2 Ng4 {So it is impossible to get in f4 here.}) 5. Nge2 d6 6. O-O (6. a3 $1) 6... O-O 7. f4 (7. a3 $1) 
  
  ```
  
  .
  
  ```
   [fen "rnbqkbnr/pppppppp/8/8/2B1P3/2NP1P2/PPP1N1PP/R1BQK2R w KQ - 0 1"]
  
  ```
  
  .
  
  > **Comments:**
  > **username_0**: f3 could be played if the plan is to castle queenside in the near future, or just do it first before f3. The normal London can often be played in various orders, and c3 usually comes pretty late, so f3 here in the mirror would hopefully come rather late too. Only real question is where to put the other Bishop. I often struggle with that when playing the London.  
  > **username_2**: In my opinion, f3 would still serve little purpose even with long castling. At best, you would want to hold off on it for as long as possible.  
  
  ---
  
  ### Answer by username_4 on 2020-02-20. Score: 4
  
  Unaware of any special name given to that full sequence of moves, especially as a 'system' as opposed to an opening variation name.
  
  f3 is a major mistake and would not be played except by beginners. there is a difference between qp and kp setups so that they cannot be mirrored well like you asked.
  
  Some of the previous move sequences do have a name. It would roughly fit in the bishops opening or some others depending on what black did.
  
  I found some games of 2500+ players using those moves up to f3 which is terrible bad and white won 3 of the ones I tracked in detail based on most likely moves according to one tablebase.
  
  Which I suspect is that winning is more because of the unusualness than the soundness. The position at that point is dead even and any winning came much later from other moves.
  
  The opening is unusual but playable although apparently not at the GM level for black which further reinforces my belief that the value comes from what happens later and depends how both sides play.
  
  > **Comments:**
  > **username_0**: f3 could be played if castling queenside. See comment on username_2's answer.  
  > **username_4**: true  but f3 is still bad.  as username_2 said there are no compensating advantages.  
  
  ---
  
  ### Answer by username_5 on 2022-05-11. Score: -2
  
  A reverse London would be either a slav or a caro-kann. It's a perfectly viable idea to play although most GMs might not like it because there are some drawish lines. If that's an idea that appeals to you, you can build a very simple opening rep. There's a lot of books, most of them will refer to it as a triangle system (based on the pawn structure with e6, d5, c6- which forms a triangle)
  
  I don't understand the other answers. They seem to be focusing on specific lines rather than what the question is actually asking.
  
  > **Comments:**
  > **username_6**: The question asks about a *horizontal* mirror (so it's still a White opening), not a *vertical* one.  
  
  ---
  
  