user7147: I occasionally think it might be fun to play a chess variant that is exactly the same as regular chess, except that it is permitted to capture your own pieces as well as your opponent's pieces - so, for example, if your king was alone on the back rank with some pawns in front of it, and your opponent moved a rook or queen to the back rank and that attacking piece could not be legally captured (which would be checkmate in normal chess), it might be possible in such a variant to escape checkmate if the king could "capture" one of it's own pawns in front of it.  In the way I imagine this variant, "friendly" pieces captured in this way would be removed from play permanently, just as an opponent's piece would be - so (in this example), you've jettisoned some of your own material (which is now gone for good), but at least you were able to save yourself from checkmate...
I can imagine other scenarios where it might also be useful to give up some of your own material by "capturing" it like this, in support of the greater good....
Is this a known chess variant, does it have a name that people might recognize?  I've tried searching around and haven't been able to locate any discussions of a variant like this - but I can't be the first person to think about this.
Just as full disclosure, the only variant I really know anything about is bughouse, I'm not familiar with other variants, so I'm not sure I'm even Google searching for the right words...

user9363: A recent paper investigating how chess variants change the game calls this variant simply self-capture chess. This paper used neural-network AIs to play through many games to find patterns of play. According to the paper's authors, they found that self-captures happened not infrequently and in some interesting ways.

Self-capture moves can be used to open files and squares for the pieces in the attack; opening up a blockade by sacrificing a pawn in the pawn chain; or in defence, while escaping the mating net.


user13230: There is a variant called 'Recycle Chess' which allows that.
You can play it at brainking: https://brainking.com/en/GameRules?tp=98; it's actually a lot of fun.

user8083: There are several such chess variants.
One is "free capture chess" which is almost the same as "bicapture" (only different in the way to check the own king). In german the first one is called "Reformschach". 
For the german definition see
https://www.dieschwalbe.de/lexikon.htm
All this kind of funny variations are used in chess problems.
Actually I know only one problem using free capture chess, see https://pdb.dieschwalbe.de/P1317666

user3819: Browsing the "modest variants" at chessvariants.com, I found Option Suicide Chess by A. Black as the closest match. Besides self-capture it allows also captureless removal of own pieces and even self-capture with removal of the own capturing piece.

user20569: In German, we would call this "Schlagschach". The German Wikipedia translates this to "Capturechess".
However, I could not find an English resource that describes this variant.
But there is a thread on chess.com where someone asked about the exact same thing.
Edit: Thanks to @bitchaser who dug that thread more thoroughly and found a link to another page that calls this variant "Self-Eliminator", which states:

John Gallicano and Steve Mann invented this variant in 1997.

There is also a Java applet on that page, which is not easy to use nowadays, since for security reasons, modern browsers just don't support Java applets anymore.

I hope, this is not too off-topic for Chess.SE, but for those of you, who are interested, here follows a short instruction on how to run the game, nonetheless:

first, make sure you have the tool appletviewer on your PC. If not, you have to install the Java 8 JDK or earlier, since the tool is deprecated since Java 9. Make sure, it's the JDK, not JRE.
second, download the following files of the applet and put them all in the same folder:


https://www.chessvariants.com/play/erf/SelfElim.html (the html code is enough, no pictures, CSS or scripts are required)
https://www.chessvariants.com/play/erf/SelfElim.class
https://www.chessvariants.com/play/erf/EasyChss.class
https://www.chessvariants.com/play/erf/Chsq.class
https://www.chessvariants.com/play/erf/Chmo.class
https://www.chessvariants.com/play/erf/CB10_10.class

last, navigate to that folder and run the following command in a terminal: appletviewer file:SelfElim.html

The applet should pop up and show you the game screen:


7147: <p>I occasionally think it might be fun to play a chess variant that is exactly the same as regular chess, except that it is permitted to capture your own pieces as well as your opponent's pieces - so, for example, if your king was alone on the back rank with some pawns in front of it, and your opponent moved a rook or queen to the back rank and that attacking piece could not be legally captured (which would be checkmate in normal chess), it might be possible in such a variant to escape checkmate if the king could "capture" one of it's own pawns in front of it.  In the way I imagine this variant, "friendly" pieces captured in this way would be removed from play permanently, just as an opponent's piece would be - so (in this example), you've jettisoned some of your own material (which is now gone for good), but at least you were able to save yourself from checkmate...</p>

<p>I can imagine other scenarios where it might also be useful to give up some of your own material by "capturing" it like this, in support of the greater good....</p>

<p>Is this a known chess variant, does it have a name that people might recognize?  I've tried searching around and haven't been able to locate any discussions of a variant like this - but I can't be the first person to think about this.</p>

<p>Just as full disclosure, the only variant I really know anything about is bughouse, I'm not familiar with other variants, so I'm not sure I'm even Google searching for the right words...</p>
 9363: <p>A <a href="https://arxiv.org/pdf/2009.04374.pdf" rel="nofollow noreferrer">recent paper investigating how chess variants change the game</a> calls this variant simply <strong>self-capture</strong> chess. This paper used neural-network AIs to play through many games to find patterns of play. According to the paper's authors, they found that self-captures happened not infrequently and in some interesting ways.</p>
<blockquote>
<p>Self-capture moves can be used to open files and squares for the pieces in the attack; opening up a blockade by sacrificing a pawn in the pawn chain; or in defence, while escaping the mating net.</p>
</blockquote>
 13230: <p>There is a variant called 'Recycle Chess' which allows that.<br>
You can play it at <em>brainking</em>: <a href="https://brainking.com/en/GameRules?tp=98" rel="noreferrer">https://brainking.com/en/GameRules?tp=98</a>; it's actually a lot of fun.</p>
 8083: <p>There are several such chess variants.
One is "<strong>free capture chess</strong>" which is almost the same as "<strong>bicapture</strong>" (only different in the way to check the own king). In german the first one is called "<strong>Reformschach</strong>". 
For the german definition see
<a href="https://www.dieschwalbe.de/lexikon.htm" rel="noreferrer">https://www.dieschwalbe.de/lexikon.htm</a></p>

<p>All this kind of funny variations are used in chess problems.
Actually I know only one problem using free capture chess, see <a href="https://pdb.dieschwalbe.de/P1317666" rel="noreferrer">https://pdb.dieschwalbe.de/P1317666</a></p>
 3819: <p>Browsing the "modest variants" at chessvariants.com, I found <a href="https://www.chessvariants.com/rules/option-suicide-chess" rel="noreferrer">Option Suicide Chess</a> by A. Black as the closest match. Besides self-capture it allows also captureless removal of own pieces and even self-capture with removal of the own capturing piece.</p>
 20569: <p>In German, we would call this "Schlagschach". The <a href="https://de.wikipedia.org/wiki/Schachvariante#Schlagschach_oder_Capturechess" rel="nofollow noreferrer">German Wikipedia</a> translates this to "Capturechess".</p>

<p>However, I could not find an English resource that describes this variant.
But there is a <a href="https://www.chess.com/forum/view/general/quottake-your-own-piecesquot-chess-variant" rel="nofollow noreferrer">thread on chess.com</a> where someone asked about the exact same thing.</p>

<p><strong>Edit</strong>: Thanks to @bitchaser who dug that thread more thoroughly and found a link to another page that calls this variant "<a href="https://www.chessvariants.com/difftaking.dir/selfeliminator.html" rel="nofollow noreferrer">Self-Eliminator</a>", which states:</p>

<blockquote>
  <p>John Gallicano and Steve Mann invented this variant in 1997.</p>
</blockquote>

<p>There is also a <a href="https://www.chessvariants.com/play/erf/SelfElim.html" rel="nofollow noreferrer">Java applet on that page</a>, which is not easy to use nowadays, since for security reasons, modern browsers just don't support Java applets anymore.</p>

<hr>

<p>I hope, this is not too off-topic for Chess.SE, but for those of you, who are interested, here follows a short instruction on how to run the game, nonetheless:</p>

<ul>
<li>first, make sure you have the tool <code>appletviewer</code> on your PC. If not, you have to install the Java 8 JDK or earlier, since the tool is deprecated since Java 9. Make sure, it's the <em>JDK</em>, not <em>JRE</em>.</li>
<li>second, download the following files of the applet and put them all in the same folder:

<ul>
<li><a href="https://www.chessvariants.com/play/erf/SelfElim.html" rel="nofollow noreferrer">https://www.chessvariants.com/play/erf/SelfElim.html</a> (the html code is enough, no pictures, CSS or scripts are required)</li>
<li><a href="https://www.chessvariants.com/play/erf/SelfElim.class" rel="nofollow noreferrer">https://www.chessvariants.com/play/erf/SelfElim.class</a></li>
<li><a href="https://www.chessvariants.com/play/erf/EasyChss.class" rel="nofollow noreferrer">https://www.chessvariants.com/play/erf/EasyChss.class</a></li>
<li><a href="https://www.chessvariants.com/play/erf/Chsq.class" rel="nofollow noreferrer">https://www.chessvariants.com/play/erf/Chsq.class</a></li>
<li><a href="https://www.chessvariants.com/play/erf/Chmo.class" rel="nofollow noreferrer">https://www.chessvariants.com/play/erf/Chmo.class</a></li>
<li><a href="https://www.chessvariants.com/play/erf/CB10_10.class" rel="nofollow noreferrer">https://www.chessvariants.com/play/erf/CB10_10.class</a></li>
</ul></li>
<li>last, navigate to that folder and run the following command in a terminal: <code>appletviewer file:SelfElim.html</code></li>
</ul>

<p>The applet should pop up and show you the game screen:</p>

<p><a href="https://i.stack.imgur.com/jH9Sa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jH9Sa.png" alt="applet screenshot"></a></p>
