Answers.Body: <p>The Lucena is one of the most important endgame positions to know, and the nickname for it helps a bunch when trying to figure it out over the board. Remember this phrase - "Building a Bridge."</p>
  
  <p>The idea is to <strong>get your rook to the fourth rank</strong>. Although the move looks rather odd, the idea is simple. Once you bring your king out, he needs to be protected. Your king can advance all the way to the fifth rank, and after the check the rook can block and your pawn can queen. Allow me to use your example to demonstrate the Lucena:</p>
  
  <pre><code>[fen "1K1k4/1P6/8/8/8/8/r7/2R5 w - - 4 1"]
  
  1. Rd1+ Ke7 2. Rd4! Rb2 3. Kc7 (3. Ra4 Kd7 4. Ka7 Kc7 5. b8=Q+ Rxb8 6. Rc4+ {works as well, as referenced by @dfan in the comments}) Rc2+ 4. Kb6 Rb2+ 5. Kc6 Rc2+ (5... Rb1 6. Rd5! Rc1+ 7. Rc5 Rb1 8. Rb5) 6. Kb5! Rb2+ 7. Rb4
  </code></pre>
  
  <p>And the pawn queens easily. The very first check is important because it <strong>forces the opposing king an extra file away from the queening square.</strong> As you can see, in the final position the black king is one tempo too slow to stop the pawn from reaching the eighth rank.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-06-28T18:53:25.060Z
Answers.Text: Another useful trick, if Black puts the rook behind the pawn as he did here with 2...Rb2 rather than 2...Ra1 (which would require the bridge), is 3.Ra4 Kd7 4.Ka7 (not 4.Ka8? or Black will capture the pawn with check) Kc7 5.b8Q+ Rxb8 6.Rc4+ Kd6 7.Kxb8.
Answers.UserDisplayName: dfan
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-13T22:48:50.427Z
Answers.Text: Edited with your recommendation!
Answers.UserDisplayName: Andrew Ng
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-10-11T04:24:32.610Z
Answers.Text: @dfan, 4.Ka8 works just as well as 4.Ka7 in your 3.Ra4 line, as long as it's followed up differently. E.g. 4.Ka8 Kc7 5.Rc4+ and White ends up with the same sort of K+R v. K ending as in the 4.Ka7 line. (Incidentally, the 5.Rc4+ idea works after 4.Ka7 too.)
Answers.UserDisplayName: ETD
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Answers.CreationDate: 2013-10-12T00:07:54.747Z
Answers.Text: True, 4.Ka8 is only an error if White attempts to follow it up as in my 4.Ka7 line.
Answers.UserDisplayName: dfan
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Answers.LastEditDate: 2013-06-28T20:51:05.833Z
Answers.UserDisplayName: Andrew Ng
Body: <p>For the ones that never heard of the <a href="http://en.wikipedia.org/wiki/Lucena_position">Lucena position</a>, it a position where we have a <code>KRP+KR</code> ending, and the side with the extra pawn has his king in front of the pawn.</p>
  
  <p>The problem is that when you try to move the king out of the pawn's way, the enemy rook will deliver annoying checks that will not stop unless you are familiar with the Lucena position and setup your rook in a certain way that will eventually be able to block the checks from the enemy rook.</p>
  
  <p><strong>(example of not knowing how to Lucena)</strong></p>
  
  <pre><code>[fen "1K1k4/1P6/8/8/8/8/r7/2R5 w - - 4 1"]
  
  1. Rd1+ Ke7 2. Kc7 Rc2+ 3. Kb8 Ke6 4. Ka7 Ra2+ 5. Kb6 Rb2+ 6. Kc6 Rc2+ 7. Kb5 Rb2+ 8. Kc6 Rc2+ 9. Kb6 Rb2+ 10. Ka7 Ra2+ 11. Kb8 *
  </code></pre>
  
  <p>How do I use the Lucena position in my favor?</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-06-28T18:12:50.050Z
Comments.Text: I am planning to self-answer this at some point, telling about the importance of that little triangulation that makes everything possible, scenarios of when to put the rook on the 5th and 4th rank. But I need to research more
Comments.UserDisplayName: ajax333221
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-06-28T18:47:49.190Z
Comments.Text: isn't this a way to "steal" points in stackexchange?
Comments.UserDisplayName: Purefan
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-06-28T18:50:48.760Z
Comments.Text: To the extent of my knowledge, there is no scenario where the rook goes to the 5th rank. That is, unless you're playing semantics and you have the black pieces :)
Comments.UserDisplayName: Andrew Ng
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-06-28T18:59:55.957Z
Comments.Text: @Purefan No, answering one's own question, even immediately, is [encouraged in Stack Exchange](http://chess.stackexchange.com/help/self-answer). Now, *accepting* your own answer is not possible for 48 hours (and even then you do not get reputation points from it), to give others incentive to answer as well. If your Q&A is good, we don't want to miss it! If it's bad, it'll be downvoted. There is no "stealing" involved.
Comments.UserDisplayName: Daniel
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-06-28T19:32:11.973Z
Comments.Text: @Andrew Ng White Ke6, Rf4, Pd7, Black Kg7, Rd2. White can play 1.Rf5 to make a 5th-rank bridge because Black doesn't gain anything by "attacking" it with 1...Kg6. I got this example from Bernd Rosen's _Chess Endgame Training_.
Comments.UserDisplayName: dfan
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Comments.CreationDate: 2013-06-28T20:48:39.527Z
Comments.Text: @dfan I see - I stand corrected. It appears that black's last move was Rd1-d2 where he opted for keeping the rook on the d-file instead of going to e1 for check. I'll add this variation to my answer. Thank you for the information!
Comments.UserDisplayName: Andrew Ng
Tags: <analysis><endgame><rook-endgame>
Title: How to win using Lucena position?
ThreadText: # How to win using Lucena position?
  
  (Asked by: username_0 on 2013-06-28)
  
  For the ones that never heard of the Lucena position, it a position where we have a KRP+KR ending, and the side with the extra pawn has his king in front of the pawn.
  The problem is that when you try to move the king out of the pawn's way, the enemy rook will deliver annoying checks that will not stop unless you are familiar with the Lucena position and setup your rook in a certain way that will eventually be able to block the checks from the enemy rook.
  (example of not knowing how to Lucena)
  [fen "1K1k4/1P6/8/8/8/8/r7/2R5 w - - 4 1"]
  
  1. Rd1+ Ke7 2. Kc7 Rc2+ 3. Kb8 Ke6 4. Ka7 Ra2+ 5. Kb6 Rb2+ 6. Kc6 Rc2+ 7. Kb5 Rb2+ 8. Kc6 Rc2+ 9. Kb6 Rb2+ 10. Ka7 Ra2+ 11. Kb8 *
  
  How do I use the Lucena position in my favor?
  
  **Tags:** analysis, endgame, rook-endgame
  
  > **Comments:**
  > **username_0**: I am planning to self-answer this at some point, telling about the importance of that little triangulation that makes everything possible, scenarios of when to put the rook on the 5th and 4th rank. But I need to research more  
  > **username_1**: isn't this a way to "steal" points in stackexchange?  
  > **username_2**: To the extent of my knowledge, there is no scenario where the rook goes to the 5th rank. That is, unless you're playing semantics and you have the black pieces :)  
  > **username_3**: @username_1 No, answering one's own question, even immediately, is [encouraged in Stack Exchange](http://chess.stackexchange.com/help/self-answer). Now, *accepting* your own answer is not possible for 48 hours (and even then you do not get reputation points from it), to give others incentive to answer as well. If your Q&A is good, we don't want to miss it! If it's bad, it'll be downvoted. There is no "stealing" involved.  
  > **username_4**: @username_2 White Ke6, Rf4, Pd7, Black Kg7, Rd2. White can play 1.Rf5 to make a 5th-rank bridge because Black doesn't gain anything by "attacking" it with 1...Kg6. I got this example from Bernd Rosen's _Chess Endgame Training_.  
  > **username_2**: @username_4 I see - I stand corrected. It appears that black's last move was Rd1-d2 where he opted for keeping the rook on the d-file instead of going to e1 for check. I'll add this variation to my answer. Thank you for the information!  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2013-06-28. Score: 10
  
  The Lucena is one of the most important endgame positions to know, and the nickname for it helps a bunch when trying to figure it out over the board. Remember this phrase - "Building a Bridge."
  The idea is to get your rook to the fourth rank. Although the move looks rather odd, the idea is simple. Once you bring your king out, he needs to be protected. Your king can advance all the way to the fifth rank, and after the check the rook can block and your pawn can queen. Allow me to use your example to demonstrate the Lucena:
  [fen "1K1k4/1P6/8/8/8/8/r7/2R5 w - - 4 1"]
  
  1. Rd1+ Ke7 2. Rd4! Rb2 3. Kc7 (3. Ra4 Kd7 4. Ka7 Kc7 5. b8=Q+ Rxb8 6. Rc4+ {works as well, as referenced by @username_4 in the comments}) Rc2+ 4. Kb6 Rb2+ 5. Kc6 Rc2+ (5... Rb1 6. Rd5! Rc1+ 7. Rc5 Rb1 8. Rb5) 6. Kb5! Rb2+ 7. Rb4
  
  And the pawn queens easily. The very first check is important because it forces the opposing king an extra file away from the queening square. As you can see, in the final position the black king is one tempo too slow to stop the pawn from reaching the eighth rank.
  
  > **Comments:**
  > **username_4**: Another useful trick, if Black puts the rook behind the pawn as he did here with 2...Rb2 rather than 2...Ra1 (which would require the bridge), is 3.Ra4 Kd7 4.Ka7 (not 4.Ka8? or Black will capture the pawn with check) Kc7 5.b8Q+ Rxb8 6.Rc4+ Kd6 7.Kxb8.  
  > **username_2**: Edited with your recommendation!  
  > **username_5**: @username_4, 4.Ka8 works just as well as 4.Ka7 in your 3.Ra4 line, as long as it's followed up differently. E.g. 4.Ka8 Kc7 5.Rc4+ and White ends up with the same sort of K+R v. K ending as in the 4.Ka7 line. (Incidentally, the 5.Rc4+ idea works after 4.Ka7 too.)  
  > **username_4**: True, 4.Ka8 is only an error if White attempts to follow it up as in my 4.Ka7 line.  
  
  ---
  
  