Not nearly developed enough to be disregarded as a losing symmetrical variation. It's only the first move of eachplayer! Black has plenty of flexibility. White goes Nimzo-Larsen with 2. b3 and black responds by grabbing the center with d5. White plays d4, Black can still play symmetrically and hope to convert to the Tarrasch Defense.

I actually like this opening.

this sucks

for black

i use this opening

Honestly, as a frequent 1. Nf3 player, I find this reply by black to be the most annoying and the most accurate. I like to maintain complete flexibility, and to retain the ability to steer the game into a queen's pawn opening if I want to. Seemingly logical moves like 1...d5, 1...Nc6, 1...c5, 1...e6, and so on are just way too commital. One might play 1...d5 thinking it is "agressive", and after 2. d4 suddenly find oneself in the middle of a classical queen's gambit position. If one plays something other than the QGD, QGA, or Slav, this can be a big problem. Also, after 1...Nc6 2. d4, black is in a bit of trouble, unless he happens to be a big Chigorin defense fan. Others on this thread have mentioned this point already, but it bears repeating. When facing 1. Nf3, you simply HAVE to keep transpositional possiblities in mind, or you might end up in an entirely unfamiliar position.

This is how I play against 1. nf3 makes white set the pace and you gain the effect of not having to show. White can play queen pawn, english or stay true to the Zukatort with g3 or b3

everybody knows this so obvious

non sense

....

This might be good for some, but I'd opt for d6 or c5 before I would this.

It's a good one, one should not knock it if one knows nought about it, yo!

This is the best defense to Nf3.  It forces white to show his hand.  As to the gent who says symmetrical play is breaking principle, I think that only applies to moves after 2 or 3.  By your logic then 1.e4 e5 and 1.d4 d5 would be symmetrical play and therefore breaking principle.

I personally play Nf3 hoping for d5.  It allows c4 the Reti Gambit or standard 'hypermodern' play.  This can quickly take your opponent out of book.  If my opponent plays Nf6 then the ball is in my court and I'm forced to play safer/standard chess.  And the opposite is true for me too, if white plays Nf3 I immediately play Nf6 and see what kind of attack he's going for.  It allows me a move to decide on the right plan.

~boog

Only two moves but it is not the shortest opening.

Magicnerd has it right, this is TWO MOVES and I use this all the time, playing a KID formation and I have a pretty good score with it.

That's Not An Opening? That's Two Moves.

It is simply not possible to evaluate this position. 

Wrong move by black ! Symmetrical playing leads to a loss if you are black .. principle .

Won as white each time black played the symmetrical variation