user15543: Is there a general consensus among composers, players, and/or organizations for what exactly defines an en passant checkmate, and is there any history  to it?
As far as I know, there are two possibilities to define it by.

The pawn captures, moving to deliver a discovered check that results in checkmate.

The pawn captures, and the pawn itself checkmates.



user70: I don't think it is defined at all.  But in your first case, the pawn is delivering the mate. So I think that would be the 'en passant mate'.  The 2nd case is 'just' a discovered mate.

user17911: After some research I could not find  any "official" definition by a chess association/federation. This doesn't really surprise me, as there really is no need for a definition of "e.p. checkmate" to ensure correct play.
However the general internet consensus on the usage of the term seems to agree on the following requirements:

The game has to end with checkmate.
The last move has to be played en passant.

An exemplary notated move would be "29... cxd e.p. #" (although notating e.p. is optional under the FIDE laws of chess (C.9)) - regardless if the pawn capturing delivers check or not. The Wikipedia examples follow this definition.
As there is no opinion by a regulatory instance about this topic, it seems to be up to you to make up your mind on this topic or bringing it to the attention of said regulatory instance. I am taking the "democratic" approach with the above definition.

15543: <p>Is there a general consensus among composers, players, and/or organizations for what exactly defines an en passant checkmate, and is there any history  to it?</p>
<p>As far as I know, there are two possibilities to define it by.</p>
<ol>
<li><p>The pawn captures, moving to deliver a discovered check that results in checkmate.</p>
</li>
<li><p>The pawn captures, and the <em>pawn itself</em> checkmates.</p>
</li>
</ol>
 70: <p>I don't think it is defined at all.  But in your first case, the pawn is delivering the mate. So I think that would be the 'en passant mate'.  The 2nd case is 'just' a discovered mate.</p>
 17911: <p>After some research I could not find  any "official" definition by a chess association/federation. This doesn't really surprise me, as there really is no need for a definition of "e.p. checkmate" to ensure correct play.</p>

<p>However the general internet consensus on the usage of the term seems to agree on the following requirements:</p>

<ul>
<li>The game has to end with checkmate.</li>
<li>The last move has to be played en passant.</li>
</ul>

<p>An exemplary notated move would be "<strong>29... cxd e.p. #</strong>" (although notating e.p. is optional under the <em>FIDE laws of chess (C.9)</em>) - regardless if the pawn capturing delivers check or not. The <a href="https://en.wikipedia.org/wiki/En_passant#Unusual_examples" rel="nofollow noreferrer">Wikipedia examples</a> follow this definition.</p>

<p>As there is no opinion by a regulatory instance about this topic, it seems to be up to you to make up your mind on this topic or bringing it to the attention of said regulatory instance. I am taking the "democratic" approach with the above definition.</p>
