Longest individual notation?

What is the longest standard annotation that can be made on a single move? 

The longest I can think of is "fxe8=Q#" or something to that effect (where a pawn captures to promote and mate). Is there anything that uses more characters?

P.S By "standard annotation", I am just excluding commentary such as ??, ?! etc, as you can put as many exclamation points as you want (in theory).

Thank you

Maybe dxc6e.p.+, I guess?

Something like Qa1xe4+ is equal in length to what you have. This would only be used if you had promoted a couple extra queens, and had one on a4 and e1 as well (for example), as Qaxe4+ and Q1xe4+ would both be ambiguous. Same thing with enough knights or bishops, but not rooks.

But with an e.p. capture, is it necessary to cite it as an e.p. capture? (ie wouldn't that just be cited as dxc6+ regardless, with the knowledge that the capture was e.p.?) 

Ah yes! That's more creative

Actually the en passant notation is not really compulsory, but you will notice that some chess websites include e.p. in their notations while other websites do not do so. The notation just makes things less ambiguous. Imagine that a player trying to analyse a game does not know about the en passant rule, and suddenly a dxc6 appears in the notations of the game played even though the Black pawn was on d5. To the player, he will be astonished that the book displays 'dxc6' since to him/her, captures cannot be made that way. Writing e.p., then, makes things clearer to the player, in the sense that the move played is special in some way.

Ah yeah fair enough. I suppose it is best to be clear.

So you might have me beat there (do periods count though? )

fxe8=Q# is the same length as 0-0-0!! with the exclamation points. 

I did say no commentary (! or ?), but if I was playing that game, I could propose fxe8=Q#?? or even fxe8=Q#???!?!

Yeah nice try. I think that's 7 characters. 
And not totally necessary, as we don't yet have two pieces occupying one square. 

On that note, will Chess.com bring in multi-layer chess?? lol

In my OP, I did say 'could happen'. This is just a hypothetical situation.

In some cases, players leave a weak back rank. Where there is the need for this rank to be protected, there is the potential for the protecting piece to be captured. This capturing move could even lead to a #. 

Not really, it can simply be written as dxc6ep+, so the length is equal. It's very difficult to find further than 7 characters in the notation though.

Ok thank you @eric0022. 
This was fun

Or you could just, you know, play Qxe8#. Just ignore me.

You could, but why not change things up a bit?

Isn't the move number part of the notation? But not sure how high a move number can be. Is this possible? (extended from work above)

1. Nf3 Nf6
2. d4 e6
3. e3 c5
4. c4 d5
5. dc5 Bc5
6. Nc3 Bb4
7. Bd2 dc4
8. Bc4 O-O
9. O-O Nc6
10. Qe2 Qe7
11. e4 Bc3
12. Bc3 e5
13. Qe3 Be6
14. Be2 Ng4
15. Qc1 Rac8
16. h3 Nh6
17. Qe3 f6
18. a3 Nf7
19. b4 a6

...and so on...

999. Ra3 Nb4

1000. Qa1xe4+

That's 13 characters including the space!

Hmmmm. I am not sure whether the move number is included. If so, I wonder how high the move number could go??

Ok so I did a look. In theory, the game can continue infinitely if the players don't claim a draw (for repetition etc). It makes you wonder....

Many pawn moves can ocur in games, each of which resets the 50-move count. Probably the game can extend to like 2000 moves? (if White is the player to wipe out the entire army of Black, then the maximum number of pawn pushes is 6 x 8 = 48, while the maximum number of captures is 15, so the absolute maximum number of moves in the game without a 50 move rule being claimed is (48 + 15 + 1) x 50 = 3200, while the maximum number of moves without meeting the 75 move automatic draw is (48 + 15 + 1) x 75 = 4800, but it is hard to achieve the first 50 moves without captures, pawn pushes and breaching the threefold repetition rule).

Yeah nice.

Of course it is hard to prevent repetition of positions etc. 

Funny how we are now talking about the most possible moves in a game. 

But the longest notation (with move number) would have 4 digits in a move number, no? I think it would be nearly impossible for the move count to reach 10k. 
To try, I am thinking that it would be best to open with the knights heaps, save the pawn moves eh?