Answers.Body: <p>Yes, a piece can check even if it can't move because of a pin. This is explicitly written in the <a href="https://handbook.fide.com/chapter/E012018" rel="nofollow noreferrer">FIDE Laws of Chess</a> (emphasis added):</p>
  <blockquote>
  <p>3.9.1 The king is said to be 'in check' if it is attacked by one or more of the opponent's pieces, <strong>even if such pieces are constrained from moving to the square occupied by the king because they would then leave or place their own king in check</strong>.</p>
  </blockquote>
  <p>Therefore, if the black king tried to escape to b4 or d4 it would be moving into check, which is not allowed.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-09-02T09:53:46.207Z
Answers.Text: Also note this rule is logical. Assuming kings could be taken (they can't!!) your king would be the first to resign. (It's not uncommon for a game that both players might reach the goal, but only the first one wins...)
Answers.UserDisplayName: Hauke Reddmann
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Answers.CreationDate: 2021-09-01T19:23:24.063Z
Answers.LastActivityDate: 2021-09-01T19:30:39.947Z
Answers.LastEditDate: 2021-09-01T19:30:39.947Z
Answers.UserDisplayName: itub
Answers.Body: <p>You are in checkmate if you are in check and have no legal move by which to escape it.</p>
  <p>In this case you cannot escape check by moving your king. B4 or D4 would leave you in check from the knight, C4 would leave you in check from the bishop and anything on rows 2 or 3 would leave you in check from a rook.</p>
  <p>However moving your king is not the only way to escape a check. It is also sometimes possible to escape a check by blocking the capture route or by capturing the attackers piece. In the original version of the question it was possible to block the capture route by moving your queen to D3. So the position was not checkmate. In the revised version of the question it is not possible to block the attack path or capture the attacker so the revised position is checkmate.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-09-01T18:40:13.617Z
Answers.Text: Thank you for your answer but I now realised I made a mistake in my setup. I've edited my answer with the correct image. I wanted to emphasise on the knight's position. Is it really putting the king in check if the king moves to B4 or D4?
Answers.UserDisplayName: parhine
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Answers.CreationDate: 2021-09-01T18:33:50.027Z
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Answers.LastEditDate: 2021-09-01T18:45:01.060Z
Answers.UserDisplayName: Peter Green
Body: <p>Consider this chess board set up:</p>
  <p><a href="https://i.sstatic.net/GkpUh.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/GkpUh.png" alt="enter image description here" /></a></p>
  <p>Is the black king allowed to move to B4 or D4? The knight on C6 would put their white king in check if it moves.</p>
  <p>I haven't really read any rules about this so thought I'd ask.</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-09-01T19:44:22.580Z
Comments.Text: why don't you check it in [an engine](https://lichess.org/analysis/standard/8/5B2/1KN4q/6P1/8/2k2R2/R7/8_b_-_-_0_1)?
Comments.UserDisplayName: BCLC
Tags: <checkmate><kings>
Title: Is this king in checkmate?
ThreadText: # Is this king in checkmate?
  
  (Asked by: username_0 on 2021-09-01)
  
  Consider this chess board set up:
  
  [![enter image description here](https://i.sstatic.net/GkpUh.png)](https://i.sstatic.net/GkpUh.png)
  
  Is the black king allowed to move to B4 or D4? The knight on C6 would put their white king in check if it moves.
  
  I haven't really read any rules about this so thought I'd ask.
  
  **Tags:** checkmate, kings
  
  > **Comments:**
  > **username_1**: why don't you check it in [an engine](https://lichess.org/analysis/standard/8/5B2/1KN4q/6P1/8/2k2R2/R7/8_b_-_-_0_1)?  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2021-09-01. Score: 3 | Accepted answer
  
  Yes, a piece can check even if it can't move because of a pin. This is explicitly written in the [FIDE Laws of Chess](https://handbook.fide.com/chapter/E012018) (emphasis added):
  
  > 3.9.1 The king is said to be 'in check' if it is attacked by one or more of the opponent's pieces, **even if such pieces are constrained from moving to the square occupied by the king because they would then leave or place their own king in check**.
  
  Therefore, if the black king tried to escape to b4 or d4 it would be moving into check, which is not allowed.
  
  > **Comments:**
  > **username_3**: Also note this rule is logical. Assuming kings could be taken (they can't!!) your king would be the first to resign. (It's not uncommon for a game that both players might reach the goal, but only the first one wins...)  
  
  ---
  
  ### Answer by username_4 on 2021-09-01. Score: 2
  
  You are in checkmate if you are in check and have no legal move by which to escape it.
  
  In this case you cannot escape check by moving your king. B4 or D4 would leave you in check from the knight, C4 would leave you in check from the bishop and anything on rows 2 or 3 would leave you in check from a rook.
  
  However moving your king is not the only way to escape a check. It is also sometimes possible to escape a check by blocking the capture route or by capturing the attackers piece. In the original version of the question it was possible to block the capture route by moving your queen to D3. So the position was not checkmate. In the revised version of the question it is not possible to block the attack path or capture the attacker so the revised position is checkmate.
  
  > **Comments:**
  > **username_0**: Thank you for your answer but I now realised I made a mistake in my setup. I've edited my answer with the correct image. I wanted to emphasise on the knight's position. Is it really putting the king in check if the king moves to B4 or D4?  
  
  ---
  
  