Answers.Body: <p>I'll start an answer just to get going as kmartin suggested. 
  I'm sure it'll be superseded by other findings.</p>
  
  <p><a href="http://www.chessgames.com/perl/chessgame?gid=1536059&amp;kpage=1" rel="noreferrer">Carlsen beat Anand</a> in Linares 2009 when he was 18 years and 3 month old.</p>
  
  <p>(Other games that came to mind but narrowly miss out: <a href="http://www.chessgames.com/perl/chessgame?gid=1451947" rel="noreferrer">Carlsen beating Topalov, 2007</a>, <a href="http://www.chessgames.com/perl/chessgame?gid=1260681" rel="noreferrer">Radjabov beating Kasparov, 2003</a>)</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-05-06T07:11:19.760Z
Answers.Text: Also Giri beating Carlsen in Wijk Aan Zee 2011 doesn't count, as Carlsen wasn't WC yet.
Answers.UserDisplayName: Maxwell86
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Answers.CreationDate: 2017-05-05T13:31:39.670Z
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Answers.UserDisplayName: BlindKungFuMaster
Answers.Body: <p>If you don't mind including female chess players (I don't see any reason not to do so), I found that <strong>Maia Chiburdanidze</strong>, the seventh women's world chess champion, played a game in 1973 against the reigning champion <strong>Nona Gaprindashvili</strong>. The game was played in USSR Championship.</p>
  
  <p><em>She was only <strong>12</strong> (born in 1961) and defeated Gaprindashvili.</em></p>
  
  <p>Here is the link to the game: <a href="http://www.chessgames.com/perl/chessgame?gid=1285155" rel="nofollow noreferrer">http://www.chessgames.com/perl/chessgame?gid=1285155</a></p>
  
  <hr>
  
  <p>Maia Chiburdanidze took over the crown from Nona Gaprindashvili in 1978, aged 17.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-05-05T23:00:27.497Z
Answers.Text: "I don't see any reason not to do so" I can think of at least two: players at lower levels (i.e. Women's WCs) have a lower draw rate than open-WC-caliber players, making them more likely to lose any given game. Another is that improving one's rating becomes exponentially harder as one improves through the ranks of GMs, so the time it should take to get to the level of top women is lower than the time it should take to get to the level of top men.
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Answers.CreationDate: 2017-05-05T19:46:24.973Z
Answers.LastActivityDate: 2017-05-05T22:25:31.903Z
Answers.LastEditDate: 2017-05-05T22:25:31.903Z
Answers.UserDisplayName: kmartin
Body: <p>A simple web search doesn't seem to readily give the answer to this question. Who is the youngest player to defeat a <strong>reigning</strong> World Chess Champion in a classical chess game?</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-04-27T04:40:39.600Z
Comments.Text: Not a classical game, but Spassky beat Botvinnik in a simul when he was 10. Not sure if that has ever been tracked. I've looked at several players bios on Wikipedia, but none of them give enough details to be able to determine the answer.
Comments.UserDisplayName: Herb
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-05-04T20:54:54.487Z
Comments.Text: Since this question isn't going anywhere for more than a week, I would suggest that everyone who knows a game that could be an adept for the right answer (but isn't sure about it) can post it here and others will try to overtrump his/her answer.
Comments.UserDisplayName: kmartin
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-07-03T09:54:50.193Z
Comments.Text: At Gijón (1944), Alekhine was close to losing to 13-year-old [Arturo Pomar Salamanca](https://en.wikipedia.org/wiki/Arturo_Pomar) in a [classical game](http://www.chessgames.com/perl/chessgame?gid=1013576) that ended in a *draw*.
Comments.UserDisplayName: Sac Exchange
Tags: <history>
Title: Who is the youngest player to defeat a reigning World Chess Champion in a classical chess game?
ThreadText: # Who is the youngest player to defeat a reigning World Chess Champion in a classical chess game?
  
  (Asked by: username_0 on 2017-04-26)
  
  A simple web search doesn't seem to readily give the answer to this question. Who is the youngest player to defeat a **reigning** World Chess Champion in a classical chess game?
  
  **Tags:** history
  
  > **Comments:**
  > **username_1**: Not a classical game, but Spassky beat Botvinnik in a simul when he was 10. Not sure if that has ever been tracked. I've looked at several players bios on Wikipedia, but none of them give enough details to be able to determine the answer.  
  > **username_2**: Since this question isn't going anywhere for more than a week, I would suggest that everyone who knows a game that could be an adept for the right answer (but isn't sure about it) can post it here and others will try to overtrump his/her answer.  
  > **username_3**: At Gijón (1944), Alekhine was close to losing to 13-year-old [Arturo Pomar Salamanca](https://en.wikipedia.org/wiki/Arturo_Pomar) in a [classical game](http://www.chessgames.com/perl/chessgame?gid=1013576) that ended in a *draw*.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_4 on 2017-05-05. Score: 7
  
  I'll start an answer just to get going as username_2 suggested.
  I'm sure it'll be superseded by other findings.
  
  [Carlsen beat Anand](http://www.chessgames.com/perl/chessgame?gid=1536059&kpage=1) in Linares 2009 when he was 18 years and 3 month old.
  
  (Other games that came to mind but narrowly miss out: [Carlsen beating Topalov, 2007](http://www.chessgames.com/perl/chessgame?gid=1451947), [Radjabov beating Kasparov, 2003](http://www.chessgames.com/perl/chessgame?gid=1260681))
  
  > **Comments:**
  > **username_5**: Also Giri beating Carlsen in Wijk Aan Zee 2011 doesn't count, as Carlsen wasn't WC yet.  
  
  ---
  
  ### Answer by username_2 on 2017-05-05. Score: 4
  
  If you don't mind including female chess players (I don't see any reason not to do so), I found that **Maia Chiburdanidze**, the seventh women's world chess champion, played a game in 1973 against the reigning champion **Nona Gaprindashvili**. The game was played in USSR Championship.
  
  *She was only **12** (born in 1961) and defeated Gaprindashvili.*
  
  Here is the link to the game: <http://www.chessgames.com/perl/chessgame?gid=1285155>
  
  ---
  
  Maia Chiburdanidze took over the crown from Nona Gaprindashvili in 1978, aged 17.
  
  > **Comments:**
  > **username_6**: "I don't see any reason not to do so" I can think of at least two: players at lower levels (i.e. Women's WCs) have a lower draw rate than open-WC-caliber players, making them more likely to lose any given game. Another is that improving one's rating becomes exponentially harder as one improves through the ranks of GMs, so the time it should take to get to the level of top women is lower than the time it should take to get to the level of top men.  
  
  ---
  
  