Answers.Body: <p>This question requires concrete calculation.</p>
  <p>When you play moves like this, you lose material, but you force your opponent's king to move. Which is worth more? Well, forcing your opponent's king to move only matters if you can launch a winning attack. If opponent gets a free move they'll just play ...Kg8 and be fine, so you must have some kind of follow-up to sacrifice a Knight like that. Can you see a winning attack?</p>
  <p>The only candidate is Qh5+, and if Black were forced to play ...Ke6 in response then you might have something (venturing into an open board with a naked King is very dangerous on general grounds). If Black is forced into ...g6 that's also good for you, since Bxg6+ hxg6 Qxh8 regains your sacrificed material with interest. But in this case Black is obviously going to play ...Kg8, and then you have nothing.</p>
  <p>Before sacrificing material it's a good idea to look at what your next move(s) are going to be if opponent accepts the sacrifice.</p>
  
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Answers.Body: <p>To voluntarily sacrifice a piece you need either a concrete tactical justification (regaining material or checkmating by force) or enough positional compensation.  Here you have neither.  True, Black can't castle, but it would have taken three moves for Black to castle anyway, and 9.Nxf7? actually brings bK one move closer to safety on g8.  Play can continue 9.Nxf7 Kxf7 10.Qf3+ (or Qh5+) Kg8, and now bK has enough defenders that White has no immediate continuation, and White's Queenside RNB can't reinforce an attack any faster than Black can mobilize <em>his</em> Queenside to defend.</p>
  
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Answers.Text: Hmm.  So what makes my move different from, e.g., move 10 in this game, which the engine says is a brilliant move?  Is it just because I have fewer pieces left to attack with?https://www.chess.com/analysis/game/pgn/3TZLCHRDJE?tab=review&move=10
Answers.UserDisplayName: Mikayla Eckel Cifrese
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Answers.Text: @MikaylaEckelCifrese: The difference is that you either get immediately your material back (... Kxf7;Qf3+ and the Nd4 hangs) or, to prevent the loss of the knight, black needs to play Ke6 which opens additional possibilities for attack (consult a book about the Fried Liver Attack for reference), for instance: ... Kxf7;Qf3 Ke6; Nc3 (the knight is pinned and can't move) Ncb4 (Nce7 is hopeless); 0-0 and black is "bound by hands and feet".
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Body: <p>Specifically, I'm confused why the game review on chess.com says this move was a blunder:</p>
  <p><a href="https://i.sstatic.net/bsewyOUr.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/bsewyOUr.png" alt="enter image description here" /></a></p>
  <p>I <em>did</em> end up losing the knight, but that's what I expected to happen.  I did it on purpose to force the king down a rank so it would be easier to attack and couldn't defend itself by castling.</p>
  <p>I had just read <a href="https://www.chess.com/article/view/attacking-f7-the-good-the-bad-the-ugly" rel="nofollow noreferrer">Attacking f7: The Good, the Bad, and the Ugly -- Chess.com</a>.  Most of the &quot;good&quot; examples involved either checking the king with a bishop or forking the queen and rook with a knight, with the king as the only defender, hence sacrificing that piece in exchange for making it much harder for the opponent to defend their king.  That's what I was trying to do here and it seemed like it worked out for me, as I ended up winning.</p>
  <p>Of course, just because I won in the end doesn't mean that particular move wasn't a mistake. But I don't understand what makes my move so significantly different from all the various &quot;good&quot; examples in the linked article, that it's a blunder instead of a strategic sacrifice.</p>
  
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Comments.Text: Good question. Some dubious gambits do this, but if your opponent is prepared then it's not worth it unless you're sure you can get an advantage.
Comments.UserDisplayName: qwr
Tags: <opening><positional-play><beginner><sacrifice><attack>
Title: When is it worth it to sacrifice a knight or bishop in order to force the opponent to move the king down a rank and lose castling rights?
ThreadText: # When is it worth it to sacrifice a knight or bishop in order to force the opponent to move the king down a rank and lose castling rights?
  
  (Asked by: username_0 on 2024-05-18)
  
  Specifically, I'm confused why the game review on chess.com says this move was a blunder:
  
  [![enter image description here](https://i.sstatic.net/bsewyOUr.png)](https://i.sstatic.net/bsewyOUr.png)
  
  I *did* end up losing the knight, but that's what I expected to happen. I did it on purpose to force the king down a rank so it would be easier to attack and couldn't defend itself by castling.
  
  I had just read [Attacking f7: The Good, the Bad, and the Ugly -- Chess.com](https://www.chess.com/article/view/attacking-f7-the-good-the-bad-the-ugly). Most of the "good" examples involved either checking the king with a bishop or forking the queen and rook with a knight, with the king as the only defender, hence sacrificing that piece in exchange for making it much harder for the opponent to defend their king. That's what I was trying to do here and it seemed like it worked out for me, as I ended up winning.
  
  Of course, just because I won in the end doesn't mean that particular move wasn't a mistake. But I don't understand what makes my move so significantly different from all the various "good" examples in the linked article, that it's a blunder instead of a strategic sacrifice.
  
  **Tags:** opening, positional-play, beginner, sacrifice, attack
  
  > **Comments:**
  > **username_1**: Good question. Some dubious gambits do this, but if your opponent is prepared then it's not worth it unless you're sure you can get an advantage.  
  
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  ## 2 answers
  
  ### Answer by username_2 on 2024-05-20. Score: 2 | Accepted answer
  
  This question requires concrete calculation.
  
  When you play moves like this, you lose material, but you force your opponent's king to move. Which is worth more? Well, forcing your opponent's king to move only matters if you can launch a winning attack. If opponent gets a free move they'll just play ...Kg8 and be fine, so you must have some kind of follow-up to sacrifice a Knight like that. Can you see a winning attack?
  
  The only candidate is Qh5+, and if Black were forced to play ...Ke6 in response then you might have something (venturing into an open board with a naked King is very dangerous on general grounds). If Black is forced into ...g6 that's also good for you, since Bxg6+ hxg6 Qxh8 regains your sacrificed material with interest. But in this case Black is obviously going to play ...Kg8, and then you have nothing.
  
  Before sacrificing material it's a good idea to look at what your next move(s) are going to be if opponent accepts the sacrifice.
  
  
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  ### Answer by username_3 on 2024-05-18. Score: 2
  
  To voluntarily sacrifice a piece you need either a concrete tactical justification (regaining material or checkmating by force) or enough positional compensation. Here you have neither. True, Black can't castle, but it would have taken three moves for Black to castle anyway, and 9.Nxf7? actually brings bK one move closer to safety on g8. Play can continue 9.Nxf7 Kxf7 10.Qf3+ (or Qh5+) Kg8, and now bK has enough defenders that White has no immediate continuation, and White's Queenside RNB can't reinforce an attack any faster than Black can mobilize *his* Queenside to defend.
  
  > **Comments:**
  > **username_0**: Hmm.  So what makes my move different from, e.g., move 10 in this game, which the engine says is a brilliant move?  Is it just because I have fewer pieces left to attack with?https://www.chess.com/analysis/game/pgn/3TZLCHRDJE?tab=review&move=10  
  > **username_4**: @username_0: The difference is that you either get immediately your material back (... Kxf7;Qf3+ and the Nd4 hangs) or, to prevent the loss of the knight, black needs to play Ke6 which opens additional possibilities for attack (consult a book about the Fried Liver Attack for reference), for instance: ... Kxf7;Qf3 Ke6; Nc3 (the knight is pinned and can't move) Ncb4 (Nce7 is hopeless); 0-0 and black is "bound by hands and feet".  
  
  ---
  
  