# Chess rules question **URL:** \ **Category:** The Game Room\ **Tags:** board-card-word-game, chess\ **Created:** [February 15, 2023, 12:42am UTC](https://boards.straightdope.com/t/chess-rules-question/979805 "2023-02-15T00:42:02Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![3AxisCtrl](https://avatars.discourse-cdn.com/v4/letter/3/ecd19e/32.png) [@3AxisCtrl](https://boards.straightdope.com/u/3AxisCtrl)\ **Post date:** [February 15, 2023, 12:42am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/1 "2023-02-15T00:42:02Z")
I ran across this question recently and was amazed to have to admit that I didn’t really know the rule. Here’s the situation: White moves (say) his bishop, putting black in check. Black moves his knight onto the bishop’s diagonal, interposing it between the bishop and his king and thus blocking the check. But the white king happens to be positioned such that this knight move appears to put the white king in check. Yet does it? That black knight is pinned: it can’t move without leaving the black king in check (by the bishop) and thus can’t really be viewed as a valid threat to the white king. (Bonus points if you can cite the actual chess rule that resolves this.) ---
**Author:** ![Maserschmidt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/maserschmidt/32/18829_2.png) [@Maserschmidt](https://boards.straightdope.com/u/Maserschmidt)\ **Post date:** [February 15, 2023, 12:45am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/2 "2023-02-15T00:45:57Z")
Yes. Check by interposing piece, rule 12D. > **[US\_Chess\_Rule\_Book-%20Online\_Only\_Edition\_v7.1-1.2.11-7.19.19.pdf](https://www.uschess.org/docs/gov/chessrules/US_Chess_Rule_Book-%20Online_Only_Edition_v7.1-1.2.11-7.19.19.pdf)** > > 2.11 MB ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [February 15, 2023, 12:49am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/3 "2023-02-15T00:49:45Z")
Just to quote the rule itself > 12D. **Check by interposing piece.** > A piece blocking a check to the king of its own color, commonly referred to as interposing, can itself give check to > the enemy king. ---
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [February 15, 2023, 1:08am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/4 "2023-02-15T01:08:20Z")
Is the now-checked player obligated to get his king out of check? ---
**Author:** ![3AxisCtrl](https://avatars.discourse-cdn.com/v4/letter/3/ecd19e/32.png) [@3AxisCtrl](https://boards.straightdope.com/u/3AxisCtrl)\ **Post date:** [February 15, 2023, 1:28am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/5 "2023-02-15T01:28:14Z")
Yes, according to Rule 12C (thanks, Maserschmidt): _Check must be parried on the move immediately following._ ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [February 15, 2023, 1:59am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/6 "2023-02-15T01:59:56Z")
> [@3AxisCtrl](#): > > That black knight is pinned: it can’t move without leaving the black king in check Of course it can move. If it takes the white king the game is over, it doesn’t matter if the black king is in check. ---
**Author:** ![FlikTheBlue](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fliktheblue/32/10972_2.png) [@FlikTheBlue](https://boards.straightdope.com/u/FlikTheBlue)\ **Post date:** [February 15, 2023, 2:34am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/7 "2023-02-15T02:34:35Z")
To state the obvious, the black knight can’t move because it’s white’s turn. What happens on black’s next move, including whether or not they can move that knight, depends on what white does to get out of check. ---
**Author:** ![Petek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/petek/32/1590_2.png) [@Petek](https://boards.straightdope.com/u/Petek)\ **Post date:** [February 15, 2023, 7:34am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/8 "2023-02-15T07:34:29Z")
FIDE (the International Chess Federation) also has a similar rule about a pinned piece giving check: > [@](#): > > 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. The rule may be found here: [FIDE Handbook E. Miscellaneous / 01. Laws of Chess / FIDE Laws of Chess taking effect from 1 January 2023 /](https://handbook.fide.com/chapter/E012023) ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [February 16, 2023, 12:56am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/9 "2023-02-16T00:56:18Z")
Yeah. If we imagine a version of chess (perhaps closer to the original version) in which the King does get taken to end the game, and “check” does not force a response, then in the scenario @3AxisCtrl lays out, if White fails to move his King or take the checking knight, then Black takes the White King before anything else can happen, and Black wins. The modern rules of chess just force the players to avoid inadvertant loss of a King, but the basic logic of taking turns still apply ---
**Author:** ![Maserschmidt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/maserschmidt/32/18829_2.png) [@Maserschmidt](https://boards.straightdope.com/u/Maserschmidt)\ **Post date:** [February 16, 2023, 3:54am UTC](https://boards.straightdope.com/t/chess-rules-question/979805/10 "2023-02-16T03:54:29Z")
Like Duck Chess! > [@New chess variant: duck chess!](https://boards.straightdope.com/t/new-chess-variant-duck-chess/973213): > > [Chess.com](http://Chess.com) has added a handful of new variants, and one of them is understandably sweeping all the video bloggers. Duck chess sounds kind of dumb, but I am finding it addictive – basically, it’s just like a normal chess game, except every move you have to move a little duck around the board. What does the duck do? It’s basically a brick sitting on a square, blocking anything that tries to go through it, other than knights jumping over it. The net effect, as best I can tell so far, is substantial…