Answers.Body: <p>Kasparov in <em>My Great Predecessors, Part 4</em>:</p>
  <blockquote>
  <p>Generally speaking, Larsen's contribution to the development of opening theory is not very great, since usually he aimed to lure his opponents into little-studied variations and mainly relied on his skill in the middlegame. Nevertheless, he played a key role in the development of what is currently one of the most popular lines in the Semi-Slav Defence, the so-called improved Meran Variation: <code>1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 e6 5 e3 Nbd7 6. Bd3 dc4 7.Bc4 b5 8.Bd3 Bb7!?</code></p>
  </blockquote>
  <p>One of Larsen's ideas was to allow a check on <code>b5</code> and give up castling rights. In return he got a strong knight on <code>d5</code>. He first used this idea in the Candidate match Ivkov-Larsen 1965, see game below. Read more about it <a href="http://www.chess.com/article/view/larsenrsquos-improved-meran-the-great-dane-deigns-to-allow-check" rel="nofollow noreferrer">here</a>.</p>
  <p>Sample games:</p>
  <pre><code>  [FEN &quot;&quot;]
    [Event &quot;Larsen-Ivkov Candidates Quarterfinal Match&quot;]
    [Site &quot;Bled YUG&quot;]
    [Date &quot;1965.07.05&quot;]
    [EventDate &quot;1965.06.27&quot;]
    [Round &quot;6&quot;]
    [Result &quot;1/2-1/2&quot;]
    [White &quot;Borislav Ivkov&quot;]
    [Black &quot;Bent Larsen&quot;]
    
    1.c4 Nf6 2.Nc3 e6 3.Nf3 d5 4.d4 c6 5.e3 Nbd7 6.Bd3 dxc4 7.Bxc4
    b5 8.Bd3 Bb7 9.e4 b4 10.Na4 c5 11.e5 Nd5 12.Nxc5 Bxc5 13.dxc5
    Nxc5 14.Bb5+ Kf8 15.Qd4 Qb6 16.Be2 h6 17.O-O g6 18.Bd2 Kg7
    19.Rac1 Rac8 20.Qh4 g5 21.Qg4 Ne4 22.Rxc8 Rxc8 23.Qxe4 Nf4
    24.Qe3 Qxe3 25.fxe3 Nxe2+ 26.Kf2 g4 27.Ng1 Nxg1 28.Rc1 Rxc1
    29.Bxc1 Bxg2 30.Kxg1 Bd5 31.Bd2 Bxa2 32.Bxb4 Kg6 33.Kf2 Kf5
    34.Bc3 h5 35.Kg3 Kg5 36.h4+ Kf5 37.Bd4 a5 38.Bc3 a4 39.Bd4 Ke4
    40.Kf2 1/2-1/2
  </code></pre>
  <p>.</p>
  <pre><code>  [FEN &quot;&quot;]
    [Event &quot;1/4&quot;]
    [Site &quot;Cm  Las Palmas (06)&quot;]
    [Date &quot;1971.??.??&quot;]
    [Round &quot;6&quot;]
    [Result &quot;0-1&quot;]
    [White &quot;Wolfgang Uhlmann&quot;]
    [Black &quot;Bent Larsen&quot;]
    [ECO &quot;D47&quot;]
  
    1.c4 Nf6 2.Nc3 e6 3.Nf3 d5 4.d4 c6 5.e3 Nbd7 6.Bd3 dxc4 7.Bxc4
    b5 8.Bd3 Bb7 9.e4 b4 10.Na4 c5 11.e5 Nd5 12.Nxc5 Nxc5 13.dxc5
    Bxc5 14.Bb5+ Ke7 15.O-O Qb6 16.Bd3 h6 17.Qe2 Rhd8 18.Bd2 Kf8
    19.Rac1 Rac8 20.Rc2 a5 21.Rfc1 Kg8 22.h3 Ne7 23.Ne1 Bd4
    24.Rxc8 Rxc8 25.Rxc8+ Nxc8 26.b3 Ne7 27.Nf3 Bc5 28.Be1 Nf5
    29.Kf1 Qc6 30.Bb5 Qc7 31.Bd3 Nd4 32.Nxd4 Bxd4 33.f4 Qc1 34.Qd2
    Qa1 35.Qc2 Bc3 36.Qb1 Ba6 0-1
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-09-27T11:08:57.110Z
Answers.Text: There is something odd with the variation in the Kasparov quote : 6...Bb7 is illegal. Should it be 6.Bd3 dc4 7.Bc4 b5 8.Bd3 Bb7!? ?
Answers.UserDisplayName: Evargalo
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-09-27T12:26:11.833Z
Answers.Text: Yes, you are correct.
Answers.UserDisplayName: Dag Oskar Madsen
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-09-27T12:57:13.097Z
Answers.Text: Something happened to the first game. It doesn't show properly on my screen.
Answers.UserDisplayName: Dag Oskar Madsen
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-09-27T14:32:44.867Z
Answers.Text: It is weird because the preview when editing shows both games correctly.
Answers.UserDisplayName: Evargalo
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-09-27T15:25:53.970Z
Answers.Text: @Evargalo That is very strange - I see that as well. Looks like a bug in something to me - but don't ask me what.
Answers.UserDisplayName: Ian Bush
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2014-06-15T13:37:08.647Z
Answers.LastActivityDate: 2021-09-27T14:32:05.717Z
Answers.LastEditDate: 2021-09-27T14:32:05.717Z
Answers.UserDisplayName: Dag Oskar Madsen
Body: <p>Once when I was reading a book from Kasparov he quoted that most of the modern ideas in the semi-Slav came from Larsen games. Does anyone know good novelties that Larsen brings in this opening?   </p>
  
Tags: <opening><slav-defense><novelties>
Title: Larsen Ideas in the semi-slav
ThreadText: # Larsen Ideas in the semi-slav
  
  (Asked by: username_0 on 2014-04-23)
  
  Once when I was reading a book from Kasparov he quoted that most of the modern ideas in the semi-Slav came from Larsen games. Does anyone know good novelties that Larsen brings in this opening?
  
  **Tags:** opening, slav-defense, novelties
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2014-06-15. Score: 6 | Accepted answer
  
  Kasparov in *My Great Predecessors, Part 4*:
  
  > Generally speaking, Larsen's contribution to the development of opening theory is not very great, since usually he aimed to lure his opponents into little-studied variations and mainly relied on his skill in the middlegame. Nevertheless, he played a key role in the development of what is currently one of the most popular lines in the Semi-Slav Defence, the so-called improved Meran Variation: `1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 e6 5 e3 Nbd7 6. Bd3 dc4 7.Bc4 b5 8.Bd3 Bb7!?`
  
  One of Larsen's ideas was to allow a check on `b5` and give up castling rights. In return he got a strong knight on `d5`. He first used this idea in the Candidate match Ivkov-Larsen 1965, see game below. Read more about it [here](http://www.chess.com/article/view/larsenrsquos-improved-meran-the-great-dane-deigns-to-allow-check).
  
  Sample games:
  
  ```
    [FEN ""]
    [Event "Larsen-Ivkov Candidates Quarterfinal Match"]
    [Site "Bled YUG"]
    [Date "1965.07.05"]
    [EventDate "1965.06.27"]
    [Round "6"]
    [Result "1/2-1/2"]
    [White "Borislav Ivkov"]
    [Black "Bent Larsen"]
    
    1.c4 Nf6 2.Nc3 e6 3.Nf3 d5 4.d4 c6 5.e3 Nbd7 6.Bd3 dxc4 7.Bxc4
    b5 8.Bd3 Bb7 9.e4 b4 10.Na4 c5 11.e5 Nd5 12.Nxc5 Bxc5 13.dxc5
    Nxc5 14.Bb5+ Kf8 15.Qd4 Qb6 16.Be2 h6 17.O-O g6 18.Bd2 Kg7
    19.Rac1 Rac8 20.Qh4 g5 21.Qg4 Ne4 22.Rxc8 Rxc8 23.Qxe4 Nf4
    24.Qe3 Qxe3 25.fxe3 Nxe2+ 26.Kf2 g4 27.Ng1 Nxg1 28.Rc1 Rxc1
    29.Bxc1 Bxg2 30.Kxg1 Bd5 31.Bd2 Bxa2 32.Bxb4 Kg6 33.Kf2 Kf5
    34.Bc3 h5 35.Kg3 Kg5 36.h4+ Kf5 37.Bd4 a5 38.Bc3 a4 39.Bd4 Ke4
    40.Kf2 1/2-1/2
  
  ```
  
  .
  
  ```
    [FEN ""]
    [Event "1/4"]
    [Site "Cm  Las Palmas (06)"]
    [Date "1971.??.??"]
    [Round "6"]
    [Result "0-1"]
    [White "Wolfgang Uhlmann"]
    [Black "Bent Larsen"]
    [ECO "D47"]
  
    1.c4 Nf6 2.Nc3 e6 3.Nf3 d5 4.d4 c6 5.e3 Nbd7 6.Bd3 dxc4 7.Bxc4
    b5 8.Bd3 Bb7 9.e4 b4 10.Na4 c5 11.e5 Nd5 12.Nxc5 Nxc5 13.dxc5
    Bxc5 14.Bb5+ Ke7 15.O-O Qb6 16.Bd3 h6 17.Qe2 Rhd8 18.Bd2 Kf8
    19.Rac1 Rac8 20.Rc2 a5 21.Rfc1 Kg8 22.h3 Ne7 23.Ne1 Bd4
    24.Rxc8 Rxc8 25.Rxc8+ Nxc8 26.b3 Ne7 27.Nf3 Bc5 28.Be1 Nf5
    29.Kf1 Qc6 30.Bb5 Qc7 31.Bd3 Nd4 32.Nxd4 Bxd4 33.f4 Qc1 34.Qd2
    Qa1 35.Qc2 Bc3 36.Qb1 Ba6 0-1
  
  ```
  
  > **Comments:**
  > **username_2**: There is something odd with the variation in the Kasparov quote : 6...Bb7 is illegal. Should it be 6.Bd3 dc4 7.Bc4 b5 8.Bd3 Bb7!? ?  
  > **username_1**: Yes, you are correct.  
  > **username_1**: Something happened to the first game. It doesn't show properly on my screen.  
  > **username_2**: It is weird because the preview when editing shows both games correctly.  
  > **username_3**: @username_2 That is very strange - I see that as well. Looks like a bug in something to me - but don't ask me what.  
  
  ---
  
  