user1413: This manoeuvre is a form of pawn capturing technique. When a player’s pawn jumps two spaces on a first move, that piece can then be taken from the side as the opposing pawn moves into the moving pawn’s “lane” behind it, capturing it.
My question is, are there any other conditions where this move cannot be carried out such as to prevent check or checkmate or to carry out a check or checkmate?
Also, is this move allowed in tournaments and the like?

user12873: The best way to think of en passant is that it's a normal move in all regards, except that the opportunity to play it expires on that move.
The move can be carried out so long as it doesn't break any rules, just like any other move. So it can be used to block a check, give a check, give a checkmate, etc. But let's say your pawn is pinned to your king. If performing an en passant capture with it leaves your king exposed to an enemy attack, this is illegal and thus not allowed.

user3332: The en passant is subject to all the usual rules of chess. So you cannot use it if it would be illegal to move your pawn (for example if your king is in check and the move would not get you out of check, or if the moving pawn is pinned to the king, etc.). It is part of the official rules of chess, and is absolutely allowed in tournaments.
There is one important additional rule about en passant: it can only be used on the move following the move of the captured pawn. (Rule 3.7d) You cannot wait a few moves and then use the en passant capture.

user2297: An en passant capture is just a capture. There are no special rules other than its definition, as described in the question. Put another way, you capture the pawn as if it had only moved forward one space.
Of course, the capture isn't exempt from the rest of the rules. For example, you can't make a move that leaves your king in check, so you can't make an en passant capture that leaves your king in check. But there's nothing special about en passant captures here; all the usual rules apply.
And, yes, the rule applies in tournaments. Don't think of en passant captures as something special; despite the seeming quirkiness, they're no more special than castling, which also has its own quirky rules.

user3237: You can't take a pawn en passant if that pawn just made a discovered check to your King:
8/8/7k/8/2p5/8/3P4/2B1K3 w - - 0 1

1. d4+

After 1. d4+ Black is in check (their king is attacked by the White bishop on c1) so he has to move his King. 1...cxd3 is not allowed.
Also, it can't be carried out if your pawn is pinned to your king:
6k1/8/8/8/2p5/8/B2P4/4K3 w - - 0 1

1. d4

The Black pawn on c4 is pinned by the White Bishop on a2. If that Pawn moves, the White Bishop would be able to take the Black King. So after 1. d4 the move 1...cxd3 is not allowed.
I can't think of any other condition where this move can not be carried out.
And yes, en passant is allowed in tournaments of course. But when you take a pawn en passant, do not say "en passant" aloud (some low rated players do that, they also say "check" aloud when they put the other player's king in check) since it can break your opponent's concentration (and the concentration of the other players near you in the playing hall).
Wikipedia has a good article on the en passant rule.

1413: <p>This manoeuvre is a form of pawn capturing technique. When a player’s pawn jumps two spaces on a first move, that piece can then be taken from the side as the opposing pawn moves into the moving pawn’s “lane” behind it, capturing it.</p>

<p>My question is, are there any other conditions where this move cannot be carried out such as to prevent check or checkmate or to carry out a check or checkmate?</p>

<p>Also, is this move allowed in tournaments and the like?</p>
 12873: <p>The best way to think of en passant is that it's a normal move in all regards, except that the opportunity to play it expires on that move.</p>

<p>The move can be carried out so long as it doesn't break any rules, just like any other move. So it can be used to block a check, give a check, give a checkmate, etc. But let's say your pawn is pinned to your king. If performing an en passant capture with it leaves your king exposed to an enemy attack, this is illegal and thus not allowed.</p>
 3332: <p>The en passant is subject to all the usual rules of chess. So you cannot use it if it would be illegal to move your pawn (for example if your king is in check and the move would not get you out of check, or if the moving pawn is pinned to the king, etc.). It is part of the official rules of chess, and is absolutely allowed in tournaments.</p>

<p>There is one important additional rule about en passant: <strong>it can only be used on the move following the move of the captured pawn</strong>. (<a href="http://www.fide.com/component/handbook/?id=124&amp;view=article" rel="nofollow noreferrer">Rule 3.7d</a>) You cannot wait a few moves and then use the en passant capture.</p>
 2297: <p>An en passant capture is just a capture. There are no special rules other than its definition, as described in the question. Put another way, you capture the pawn as if it had only moved forward one space.</p>

<p>Of course, the capture isn't exempt from the rest of the rules. For example, you can't make a move that leaves your king in check, so you can't make an en passant capture that leaves your king in check. But there's nothing special about en passant captures here; all the usual rules apply.</p>

<p>And, yes, the rule applies in tournaments. Don't think of en passant captures as something special; despite the seeming quirkiness, they're no more special than castling, which also has its own quirky rules.</p>
 3237: <p>You can't take a pawn en passant if that pawn just made a discovered check to your King:</p>

<pre><code>8/8/7k/8/2p5/8/3P4/2B1K3 w - - 0 1

1. d4+
</code></pre>

<p>After 1. d4+ Black is in check (their king is attacked by the White bishop on c1) so he has to move his King. 1...cxd3 is not allowed.</p>

<p>Also, it can't be carried out if your pawn is pinned to your king:</p>

<pre><code>6k1/8/8/8/2p5/8/B2P4/4K3 w - - 0 1

1. d4
</code></pre>

<p>The Black pawn on c4 is pinned by the White Bishop on a2. If that Pawn moves, the White Bishop would be able to take the Black King. So after 1. d4 the move 1...cxd3 is not allowed.</p>

<p>I can't think of any other condition where this move can not be carried out.</p>

<p>And yes, en passant is allowed in tournaments of course. But when you take a pawn en passant, do not say "en passant" aloud (some low rated players do that, they also say "check" aloud when they put the other player's king in check) since it can break your opponent's concentration (and the concentration of the other players near you in the playing hall).</p>

<p>Wikipedia has a good article on the <a href="//en.wikipedia.org/wiki/En_passant" rel="nofollow noreferrer">en passant rule</a>.</p>
