What do you understand "en passant" refers to?

There are many ways to understand a concept. In example, the movement of the knight:

· The knight moves one square in any orthogonal direction and two squares perpendicularly (or viceversa); independent of any piece being in the way.
· The knight moves one square in any diagonal direction and one square orthogonally away from the origin (or viceversa); independent of any piece being in the way.

Both these descriptions are correct. Both are good to pass on the rule. However, most of us would agree that the first one is the standard way to interpret the move of the knight.

Likewise, the en passant rule can be described in many ways. I was surprised recently, by the way a friend got it conceived.

So I created this poll (http://www.easypolls.net/poll.html?p=5c6b4f0be4b0b3f5920c5469) so we can vote for the way in which we understand the en passant rule, to see how really wide is our way to interpret the rule.

@tomseeber Your poll is not well elaborated...

• The pawn is taken on the square it "passed", by a pawn attacking that square. <
  That is only correct if the pawn made a double step move the move before.

• The pawn is taken after it made a double move and ends up besides its opponent pawn.<
  It doesn't end up beside its opponents pawn, because the opponents pawn no longer exists.

• Also there are not many options
  --> I think things like these can be the reason why ppl vote with "Other" in such a poll.

"En passant" is french for sth like "passing by", so IMO you basically need to explain it with what it is called in another language. Immediately capturing a pawn that passed by through a double step move (only on the 4. and 5. rank, because it's only relevant there as every pawn avoiding to be captured by two step moves would land on the 4. or 5. rank)

I like your topic :) Have a nice day!

I dont see 1st explanation any standard way. I would not use even second. I always use one orthogonolan + 1 diagonal. Incidentally that is the way it defined chinese chess rules. And there it is big difference as the pony cannot jump over anything.
As of en passant you poll explanations miss the point that it must be captured on next move
and I woudl use the FIDE definition
3.7.4.1 A pawn occupying a square on the same rank as and on an adjacent file to an opponent’s pawn which has just advanced two squares in one move from its original square may capture this opponent’s pawn as though the latter had been moved only one square.
3.7.4.2 This capture is only legal on the move following this advance and is called an ‘en passant’ capture.

I feel like the FIDE definition given above describes almost exactly how I think about it in my head: the important part being "as though the latter had been moved only one square."

The poll option
"* >The pawn is taken on the square it "passed", by a pawn attacking that square. "
seems to americanize the french term and twist its meaning - the french term means "in passing" which would seem to refer to the fact that this is the only capture in chess where the capturing piece does not end up on the same square where the captured piece was.
The sentence in the poll seems to indicate a different interpretation or a kind of mnemonic that was in my mind the intended meaning.

Disclaimer: I don't actually speak any french, so someone who does should confirm this.

there was no option on your poll for:

the pawn moves two squares, then the capturing pawn gets in a DeLorean equipped with a flux capacitor, reaches a speed of 88 miles per hour, and travels back in time to the moment that the pawn passed and captures it, then returns to the normal timeline with the help a mad scientist from the past.

Pawns move one square at a time. After chess was invented they found it takes too long for games to get going, and so people agreed that they would let a pawn move two squares for its first move, in order to speed up the game. This then created problems where the opponent would claim that if it had only moved one square then he would have taken it.

So they allowed a pawn that moves two squares to be captured (by another pawn) as if it had only moved one.

Of course you cannot claim ten moves later that 'you would have taken it if it had only moved one square', as the guy that advanced it 2 some time ago would simply reply "why didn't you then?"

Hence the en-passant rule. A pawn moves two squares and you have the right to immediately capture it as if it had only moved one.

When I wrote my chess program I needed to give names to variables holding the coordinates of the various squares involved as these were needed to verify move legality: revealed checks or blocking checks for example. As a result I came up with my own way of thinking about the squares involved. A pawn that had moved 3 squares captures a pawn that has moved 2 squares, as if it had only moved 1 square.

So if fxe5(ep), I would think of f5 as the moved-3 square, e5 as the moved-2 square, and e6 as the moved-1 square.

If anyone is aware of any standard terminology for the three squares involved I'd be curious to know!

Fide definition mentioned above is the right answer.

"En passant" is also used outside chess world. If for example, I got invited a last minute for dinner. Since i am well educated, i won't come to the dinner with hands empty, i'll therefore buy "en passant" a bottle of wine... :))

@schachschachschach I omitted both "has moved two squares" and "only in the next move", only to focus on the part of the definition I was wondering about.

Actually not really me, @Vares , I know French, the term precisely means "by passing", which to me obviously means that the pawn is taken (as though it had moved one square), on the square it passed: it is taken as if it was taken in the moment it was passing, en passant.

One can argue that the pawn is taken "by passing" the potentially capturing pawn, but it doesn't seem logical to refer to the fact that the pawn surpasses the opponent pawn, instead of referring to the actual square in question, on which it is taken: where it was passing.

@petri999 Your option for the knight move is the second option, viceversa.

Thanks for the FIDE rules article. It caught me by surprise, because I had read the same article, 3.7 of the FIDE Laws of Chess, and it said different:

On 3.7.4.1 (3.7.d) at https://www.fide.com/FIDE/handbook/LawsOfChess.pdf it says:

"A PAWN ATTACKING A SQUARE CROSSED BY an opponent’s pawn which has advanced two
squares..."

BUT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I googled the text you presented, AND:

On 3.7.4.1 (3.7.d) at http://www.fide.com/component/handbook/?view=article&id=171 it says:

"A PAWN OCCUPYING A SQUARE ON THE SAME RANK as and on an adjacent file to an opponent’s pawn which has just advanced two squares..."

So @Sidonia-ChessEngine , @dav_de_brux , these are precisely the two views of the law I was curious about. It looks like not even FIDE.com agrees with FIDE.com!

Although, the first is from "FIDE Laws of Chess".-

The second, from "FIDE Laws of Chess: For competitions starting from 1 July 2014 till 30 June 2017".

I guess as the poll suggests, the first option is the most valid view.

in passing ;)

I've always defined a knight's move as a 1:2 ratio L... Sure, this could mean you could move from Nb1 to Nd5, but when teaching someone how it moves, I tell them it can only move 3 spaces from it's original point, in a 1:2 ratio L.