Simple question about chess notation

Hi all. I am generally comfortable with algebraic and descriptive, but I am blanking out on the correct way to record an en passant capture in algebraic. Suppose I am white and I have a pawn on f5. My opponent plays a pawn from g7 to g5 and I capture enpassant. Do I write fxg5 e.p. since the pawn I capture was on g5 or do I write fxg6 e.p. since my f pawn moves to g6. Either way the e.p. makes clear what is meant, but which is the officially approved way to write the move? Thanks for clarification.

Pretty sure it's fxg6, but I don't know officially.

It is fxg6 indeed.

Yeah, at a tournament when pxp I leave off the numbers and I don't write e.p. either.

Sometimes I even shorten fxg to just "fg"

Fxg Could be ambiguous. You might have pawns on f2 and f5. Your opponent could have pawns on g3 and g7.  Your opponent plays g7 to g5 and now you have two ways to capture a g pawn with an f pawn. I know these questions are about as tedious as listening to two grammarians arguing about the correct usage of commas, but I just want to get straight how "official" chess notation works.

LuftWaffles wrote:

I always write just "fxg", no "e.p."

But then, I always write like that:

1.e4 c5

2.Nf3 Nc3

3.d4 cxd

4.Nxd Nf6

I guess anything goes as long as it's unambiguous.

One way to do it is long algebraic notation. E.g. e2-e4, etc. Probably I could just google and find a lengthy pedanttic document put out be FIDE or USCF that explains "correct" notation.

http://www.chess.com/explorer/?player=Queen_of_Knight&black=0&db=3&ply=5&id=52709833 

fxg6

The FIDE Handbook containing the Laws of Chess, Appendix C Algebraic notation, paragraph C.9 answers your question:

"(...) When a pawn makes a capture, the file of departure must be indicated, then an x may be inserted, then the square of arrival. Examples: dxe5, gxf3, axb5. In the case of an ‘en passant’ capture, ‘e.p.’ may be appended to the notation. Example: exd6 e.p."

So, the x is optional (as in any capture) and the e.p is optional too. fxg or fg is not by the book even if often is unambiguous.

fg6

Record "en passant" captures as if the captured enemy pawn had just moved one square (even though it actually moved 2 squares).

Remember that "en passant" means "in passing" with the idea that an enemy foot soldier has tried to avoid fighting you by running past you.  But you swung your sword and managed to cut him down anyway.

The best way for you if you write your move down is to write after the move"e.p." So you will know exactly what you played.