Answers.Body: <p>Yes -</p>
  
  <p>A king can take two moves to go from e1 to d2 - Ke1-d1-d2 and also one move - Ke1-d2. Taking two moves is called triangulation or losing a tempo. </p>
  
  <p>A rook can take two moves to go from e1 to e3  - Re1-e2-e3 or one move - Re1-e3. Taking two moves is called losing a tempo. </p>
  
  <p>A knight cannot take one extra move to go to the same destination square.</p>
  
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Answers.Text: But a knight **can** take 2 extra moves.
Answers.UserDisplayName: Pete Becker
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Answers.Text: By that definition, if a piece returns to a square that it already visited, this would be at least a loss of tempo
Answers.UserDisplayName: Νικόλαος Μανωλακος
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Answers.Text: The point of losing a tempo is to get the same position with the other side to move. Losing two tempi defeats the purpose because the same side is still to move.
Answers.UserDisplayName: magd
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Answers.Text: Interesting. I imagine this is only to prevent zug·zwang or put your opponent in zug·zwang. Do you have examples?
Answers.UserDisplayName: Νικόλαος Μανωλακος
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Answers.Text: Here is a good example : https://www.youtube.com/watch?v=IMDmMfgb0To .
Answers.UserDisplayName: magd
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Answers.UserDisplayName: magd
Answers.Body: <p>Losing a tempo and zugzwang are normally endgame terms.  All pieces, except the Knight, can maneuver to obtain the same position, ie lose a tempo(same as playing a NULL move.)  In this position, Black would lose if it's his turn to move, so White loses a tempo with the Bishop.</p>
  
  <pre><code>
  
  [FEN "1n6/5p1p/p1p1pP1k/1pP1P1p1/1P1PB1K1/P7/8/8 w - - 0 0"]
  
  1. Bc2 Nd7 2. Bd3 Nb8 3. Be4
  </code></pre>
  
  <p>There are exceptions to retreating being bad.  In certain lines of the Ruy Lopez, the Queen's Knight retreats to allow the c pawn to advance.  In many double King Pawn openings, the King's Bishop returns to f8 to allow the Rook to put pressure on the King's Pawn and maneuver the Bishop to g7.  </p>
  
  <p>This retreat is to avoid exchanges as Black is cramped and to maintain two Knights to exploit the e5 hole.</p>
  
  <pre><code>
  [FEN "r1bq1rk1/pp1nb1pp/2p1p3/3pNp2/2PPn3/1PN1P3/PB2BPPP/R2Q1RK1 w - - 0 0"]
  
  1. Nb1! 
  </code></pre>
  
  <p>The point of these retreats is to position the pieces on a better square. This is hard to translate into program code.  Some retreating moves are for better attacking positions, Bc4-d3 to aid in the kingside attack, or for better protection of the piece, Bc4-b3 in most Sicilians.</p>
  
  <p>The other answers have provided examples where the tempo loss is the only way to win the game, so this is really important in the game.  Teaching chess is not like school, what you learn is applicable to the game.</p>
  
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Answers.UserDisplayName: Mike Jones
Answers.Body: <p>You seem to get the meaning/importance of tempo a bit wrong - it's not about getting back to the old square, it's about losing one move during the process, thus forcing the opponent to make his turn when it puts him in worse situation (this is called <a href="https://en.wikipedia.org/wiki/Zugzwang">Zugzwang</a>). This is especially important in endgames, and you can see some examples in the same wiki article you are referring to.</p>
  
  <p>Also note that the final square doesn't have to be the same as the starting one (e.g. Re1-e2-e3 instead of Re1-e3), although it often is (mainly in Kings' triangulation). Knight cannot do any of that, as mentioned in answer by @magd. Knight can just jump from and back to the same square, but the opponent can e.g. also do some repetitive move and you end up right where you started. Knight just cannot take the route to its' destination which will lose exactly one tempo (or any other odd number).</p>
  
  <p>But all other pieces (even pawns if they are at their starting square) can take an extra move while going to the destination, which in many situations enables you to force the opponent to make a move when it's a bad time for him. <a href="https://en.wikipedia.org/wiki/Triangulation_(chess)">Triangulation</a> is a classic example of this tactic.</p>
  
  <p>Generally speaking, losing tempo or just getting back to the previous square is usually bad in openings or even middlegame, although that depends on the situation. But in the endgame, deliberate loss of tempo is often maneuver which wins you the game (of course, if situation requires so).</p>
  
  <p>An example from wiki:</p>
  
  <pre><code>[fen "8/1p1k4/1P6/2PK4/8/8/8/8 w - - 0 1"]
  </code></pre>
  
  <p>If black would be on the move in this position, it would be clear victory for white, as after black King moves away, white can proceed either with his King or his Pawn (depending on the move). But white is on the move, so he must think of a way how to make it work. The answer is, lose a tempo with triangulation:</p>
  
  <pre><code>[fen "8/1p1k4/1P6/2PK4/8/8/8/8 w - - 0 1"] 
  
  1. Ke5 Kc6 2. Kd4 Kd7 3. Kd5
  </code></pre>
  
  <p>And now black is on the move, which enables white to break through.</p>
  
  <p>You are right in saying that loss of tempo is used "only" to put opponent in zugzwang, but the importance of this is greater than it might seem at first. For example, every classic mate endgame uses loss of tempo and zugzwang to get the opponent's King to the edge of the board and to mate him. You often use zugzwang without even realising that you used it. Look at the mate with Rook:</p>
  
  <pre><code>[fen "1k6/7R/2K5/8/8/8/8/8 w - - 0 1"]
  
  1. Rg7 Ka8 2. Kb6 Kb8 3. Rg8#
  </code></pre>
  
  <p>You aim to get your King to b6 when black King is on b8, so you can mate with Rook on 8th row. But you can't do that right away, as after 1. Kb6, black would get away with Kc8, and 1. Rh8+ would enable black to get away with Ka7. So in the process of getting to 8th row with your Rook, you deliberately lose a tempo with 1. Rg7 in order to win the game.</p>
  
  <p>In contrast, to address your original question, Knight is not able to do that:</p>
  
  <pre><code>[fen "8/8/8/8/8/7p/5K2/5N1k w - - 0 1"]
  
  1. Ng3+ Kh2 2. Nf1+ Kh1
  </code></pre>
  
  <p>If white could just get to the starting position with black on the move, it would be a quick victory (1... h2 2. Ng3#), but Knight can't lose a tempo, so it's impossible, which is why this position with white to move is a draw.</p>
  
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Body: <p>From <a href="https://en.wikipedia.org/wiki/Tempo_(chess)?wprov=sfsi1" rel="nofollow">Wikipedia</a>: Kings, queens, bishops, and rooks can lose a tempo; a knight cannot (Müller &amp; Pajeken 2008:40,175,189).</p>
  
  <p>Is there truth to this? Examples please. My context is towards developing an engine eval.</p>
  
  <p>Looking at a fen alone? Can we derive any info about tempo?</p>
  
  <p>Is it only about minimizing distances?</p>
  
  <p>In an engine, should we penalize moves that return to old squares? For opening or middle game?</p>
  
  <p>Is having initiative more important than tempo gains? </p>
  
  <p>If a player sees a possible  future where he will be in zug·zwang can the preempt with some tempo tricks like triangulation? Examples please?</p>
  
  <p>I see tempo gains as more of a tool for teaching. Not really having much use in the game.</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-04-19T23:52:38.013Z
Comments.Text: Can you provide a link to that Wikipedia article? The statement that you quote seems somewhat pointless, but it's out of context.
Comments.UserDisplayName: Pete Becker
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-04-20T00:48:52.853Z
Comments.Text: In context, that quote is about deliberately losing **exactly one** tempo and, indeed, a knight can't do that. It can lose two tempi, but that would seem to be rare in the context of endgame maneuvers, which is where this quote occurs.
Comments.UserDisplayName: Pete Becker
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Comments.CreationDate: 2016-04-20T14:35:23.920Z
Comments.Text: @PeteBecker Yes. And that Wikipedia article is pretty muddled/inaccurate to *define* tempo in terms of "single move" only. Because it is most definitely possible to "gain tempo" on a knight in the opening, e.g. 1.e4 e5 2.f4 exf4 3.Nf3 d6 4.d4 g5 5.h4 g4 6.Ng1. https://en.wikipedia.org/wiki/King%27s_Gambit#Fischer_Defense:_3...d6
Comments.UserDisplayName: Jeff Y
Tags: <strategy><knights><zugzwang>
Title: Why can't knights lose tempo?
ThreadText: # Why can't knights lose tempo?
  
  (Asked by: username_0 on 2016-04-19)
  
  From [Wikipedia](https://en.wikipedia.org/wiki/Tempo_(chess)?wprov=sfsi1): Kings, queens, bishops, and rooks can lose a tempo; a knight cannot (Müller & Pajeken 2008:40,175,189).
  
  Is there truth to this? Examples please. My context is towards developing an engine eval.
  
  Looking at a fen alone? Can we derive any info about tempo?
  
  Is it only about minimizing distances?
  
  In an engine, should we penalize moves that return to old squares? For opening or middle game?
  
  Is having initiative more important than tempo gains?
  
  If a player sees a possible future where he will be in zug·zwang can the preempt with some tempo tricks like triangulation? Examples please?
  
  I see tempo gains as more of a tool for teaching. Not really having much use in the game.
  
  **Tags:** strategy, knights, zugzwang
  
  > **Comments:**
  > **username_1**: Can you provide a link to that Wikipedia article? The statement that you quote seems somewhat pointless, but it's out of context.  
  > **username_1**: In context, that quote is about deliberately losing **exactly one** tempo and, indeed, a knight can't do that. It can lose two tempi, but that would seem to be rare in the context of endgame maneuvers, which is where this quote occurs.  
  > **username_2**: @username_1 Yes. And that Wikipedia article is pretty muddled/inaccurate to *define* tempo in terms of "single move" only. Because it is most definitely possible to "gain tempo" on a knight in the opening, e.g. 1.e4 e5 2.f4 exf4 3.Nf3 d6 4.d4 g5 5.h4 g4 6.Ng1. https://en.wikipedia.org/wiki/King%27s_Gambit#Fischer_Defense:_3...d6  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_5 on 2016-04-20. Score: 7 | Accepted answer
  
  You seem to get the meaning/importance of tempo a bit wrong - it's not about getting back to the old square, it's about losing one move during the process, thus forcing the opponent to make his turn when it puts him in worse situation (this is called [Zugzwang](https://en.wikipedia.org/wiki/Zugzwang)). This is especially important in endgames, and you can see some examples in the same wiki article you are referring to.
  
  Also note that the final square doesn't have to be the same as the starting one (e.g. Re1-e2-e3 instead of Re1-e3), although it often is (mainly in Kings' triangulation). Knight cannot do any of that, as mentioned in answer by @username_3. Knight can just jump from and back to the same square, but the opponent can e.g. also do some repetitive move and you end up right where you started. Knight just cannot take the route to its' destination which will lose exactly one tempo (or any other odd number).
  
  But all other pieces (even pawns if they are at their starting square) can take an extra move while going to the destination, which in many situations enables you to force the opponent to make a move when it's a bad time for him. [Triangulation](https://en.wikipedia.org/wiki/Triangulation_(chess)) is a classic example of this tactic.
  
  Generally speaking, losing tempo or just getting back to the previous square is usually bad in openings or even middlegame, although that depends on the situation. But in the endgame, deliberate loss of tempo is often maneuver which wins you the game (of course, if situation requires so).
  
  An example from wiki:
  
  ```
  [fen "8/1p1k4/1P6/2PK4/8/8/8/8 w - - 0 1"]
  
  ```
  
  If black would be on the move in this position, it would be clear victory for white, as after black King moves away, white can proceed either with his King or his Pawn (depending on the move). But white is on the move, so he must think of a way how to make it work. The answer is, lose a tempo with triangulation:
  
  ```
  [fen "8/1p1k4/1P6/2PK4/8/8/8/8 w - - 0 1"] 
  
  1. Ke5 Kc6 2. Kd4 Kd7 3. Kd5
  
  ```
  
  And now black is on the move, which enables white to break through.
  
  You are right in saying that loss of tempo is used "only" to put opponent in zugzwang, but the importance of this is greater than it might seem at first. For example, every classic mate endgame uses loss of tempo and zugzwang to get the opponent's King to the edge of the board and to mate him. You often use zugzwang without even realising that you used it. Look at the mate with Rook:
  
  ```
  [fen "1k6/7R/2K5/8/8/8/8/8 w - - 0 1"]
  
  1. Rg7 Ka8 2. Kb6 Kb8 3. Rg8#
  
  ```
  
  You aim to get your King to b6 when black King is on b8, so you can mate with Rook on 8th row. But you can't do that right away, as after 1. Kb6, black would get away with Kc8, and 1. Rh8+ would enable black to get away with Ka7. So in the process of getting to 8th row with your Rook, you deliberately lose a tempo with 1. Rg7 in order to win the game.
  
  In contrast, to address your original question, Knight is not able to do that:
  
  ```
  [fen "8/8/8/8/8/7p/5K2/5N1k w - - 0 1"]
  
  1. Ng3+ Kh2 2. Nf1+ Kh1
  
  ```
  
  If white could just get to the starting position with black on the move, it would be a quick victory (1... h2 2. Ng3#), but Knight can't lose a tempo, so it's impossible, which is why this position with white to move is a draw.
  
  
  ---
  
  ### Answer by username_3 on 2016-04-19. Score: 4
  
  Yes -
  
  A king can take two moves to go from e1 to d2 - Ke1-d1-d2 and also one move - Ke1-d2. Taking two moves is called triangulation or losing a tempo.
  
  A rook can take two moves to go from e1 to e3 - Re1-e2-e3 or one move - Re1-e3. Taking two moves is called losing a tempo.
  
  A knight cannot take one extra move to go to the same destination square.
  
  > **Comments:**
  > **username_1**: But a knight **can** take 2 extra moves.  
  > **username_0**: By that definition, if a piece returns to a square that it already visited, this would be at least a loss of tempo  
  > **username_3**: The point of losing a tempo is to get the same position with the other side to move. Losing two tempi defeats the purpose because the same side is still to move.  
  > **username_0**: Interesting. I imagine this is only to prevent zug·zwang or put your opponent in zug·zwang. Do you have examples?  
  > **username_3**: Here is a good example : https://www.youtube.com/watch?v=IMDmMfgb0To .  
  
  ---
  
  ### Answer by username_4 on 2016-04-21. Score: 2
  
  Losing a tempo and zugzwang are normally endgame terms. All pieces, except the Knight, can maneuver to obtain the same position, ie lose a tempo(same as playing a NULL move.) In this position, Black would lose if it's his turn to move, so White loses a tempo with the Bishop.
  
  ```
  
  [FEN "1n6/5p1p/p1p1pP1k/1pP1P1p1/1P1PB1K1/P7/8/8 w - - 0 0"]
  
  1. Bc2 Nd7 2. Bd3 Nb8 3. Be4
  
  ```
  
  There are exceptions to retreating being bad. In certain lines of the Ruy Lopez, the Queen's Knight retreats to allow the c pawn to advance. In many double King Pawn openings, the King's Bishop returns to f8 to allow the Rook to put pressure on the King's Pawn and maneuver the Bishop to g7.
  
  This retreat is to avoid exchanges as Black is cramped and to maintain two Knights to exploit the e5 hole.
  
  ```
  
  [FEN "r1bq1rk1/pp1nb1pp/2p1p3/3pNp2/2PPn3/1PN1P3/PB2BPPP/R2Q1RK1 w - - 0 0"]
  
  1. Nb1! 
  
  ```
  
  The point of these retreats is to position the pieces on a better square. This is hard to translate into program code. Some retreating moves are for better attacking positions, Bc4-d3 to aid in the kingside attack, or for better protection of the piece, Bc4-b3 in most Sicilians.
  
  The other answers have provided examples where the tempo loss is the only way to win the game, so this is really important in the game. Teaching chess is not like school, what you learn is applicable to the game.
  
  
  ---
  
  