because it's a wasted move, does not develop any pieces and weakens your pawn structure slightly.
Italian Game: What's wrong with h6?

That's it? It's not wasted for me if it keeps the opponent from playing Ng5...there has to be more to this than that.

I think this opening can tend to be quite dull, but the first ten moves or so have lots of scope for tactics. Playing 3...h6? is just too slow, in my opinion. I think you're better off playing 3...Nf6; if white plays 4. d3, then 4...h6 is fine as far as I can see (if still a little slow, but sound). If White plays 4. Ng5, then give 4...d5 a try.

I do give d5 a try...what else can I do once we're at that point? Is there absolutely no way to keep someone from playing Ng5? I might just forget the Two Knights Defense then...I find this move too disconcerting. Does anyone who plays the Italian have any idea?
I think h6 is ok. If you think its ok too, then play it. If it looses, then you'll know why. I know a class A player who recomends this move. But again, if it is bad, then I'm sure one of your oppenents will eventually show you why. Until then, play it!
...h6 violates most opening priciples and effectively gives White an extra half-tempo. It does nothing to add to your development and eventually can be a target. If you are that scared of the Two Knights with Ng5 play the calssical lines with 3...Bc5. Black can ill addorf to waste tempi in most lines as White just develops and gets an attack going relatively easily,

There's nothing necessarily wrong with 3...h6 (it's still in book, though much less used), but it leads to 4. d4 exd4 then depending on how white wants to play either 5. Nxd4 or, my favorite, 5. c3 dxc3 6. Nxc3 and white's down a pawn but heavily developed and has complete control over center.

I do give d5 a try...what else can I do once we're at that point? Is there absolutely no way to keep someone from playing Ng5? I might just forget the Two Knights Defense then...I find this move too disconcerting. Does anyone who plays the Italian have any idea?
It's a tricky situation for most players, when one has not studied all the main lines, but if you pull your finger out, read a decent book, put the time & effort in, then you'll be really happy with the results, for Black has a very even game if not a slightly better game if played with a cool head, normally you play d5, white tends to pxp...Nxp, & from there White has many possibilaties, but do not despair for Black can counter all & end up with a very decent middle game, it's only really tricky for one has to forsee up to around 5 to 6 moves ahead while it seems like the third world war could explode around you at any moment, but like I'm trying to say, that it's just as dangerous for White as it is for Black, but it's a great way to learn to play while the pressure is on, if you can master this as both White & Black, well then I tend to believe that you are well on your way to understand the logic, the twists & turns that you could encounter in other openings, & inhance your way of thinking & se chess in maybe a different way, Ooops, I hope that I'm not being to cloudy in my expainations, the best of luck to ya!

Exactly-- a wasted move. The consequence of spending a tempo on h6 is that white will play d4 favorably in the next 1-2 moves. The only two good moves after Bc4 are Bc5 and Nf6, two developing moves that fight for the center. Nf6 gives white less of a free hand by attacking the e4-pawn, while Bc5 directly controls d4 to make it hard for white to push.
For comparison, here are a couple mainlines of the Italian game starting with 3...Nf6
And here are some lines to compare if black plays 3...h6 instead (I invented these hastily, since I have never seen h6 played).
You should ask if you can "feel" the difference between the two sets of variations. Can you feel that black can respond to white's attempts at pushing them around more energetically in the first set of variations?
Also, if you see any patterns in the moves that get played.
Hope that helps!

The question that comes to my mind is why Black would feel he needs to prevent 4. Ng5. I play a lot of 2 Kt. defenses and I love when white plays 4. Ng5. Not because I'm such a great player or that I understand all the theory or anything or that 4. Ng5 is refutable, but because Black has such great options for interesting games, such as 4...d5 or 4...Bc5.
People talk about 3...h6 wasting a move, but the same could be said about 4. Ng5 which moves the same piece twice in the opening. Of course, just as proving 3.h6 to be detrimental may be difficult, proving 4. Ng5 to be bad is almost impossible. But it's certainly not a thing to be concerned about.
Ng5 is not a very good move by white. Its not horrible, but black has no trouble equalizing. I really like to play against it as black. I have been able to win a piece quite a few times just by knowing some theory.

I guess everyone has their own tastes. I never feel on steady ground after Black's d5 response to Ng5, the pawn exchange, etc...and there is no way I am near the level of understanding the Traxler Wilkes response.
ello,
So, here are my thoughts:
1. h6 is not that bad. At a high level it is a vaste of time.
2. I agree that d5 exd5 Na5 is quite difficult to play. Why don't you try d5 exd5 b5? And that is a really fun line. Here the best answer for white is Bf1 but I bet that most of your opponents will not make such a move.
3. Well, you play e5, Nc6 and say you're afraid of Ng5? Why do you play e5 then? If you don't like sharp games, why don't you go for the Caro-Kann, 1.e4 c6, which is very solid.
The Two Knights Defense has the opportunity for White to play Ng5 on the fourth or fifth move...I've looked up lots of info but only at The Kibitzer was there any mention of h6 to prevent Ng5 but the author said "you definitely don't want to do h6, just ask a stronger player why". He didn't want to veer off topic to explain.
Can anyone explain why I wouldn't play h6 before bringing Nf6?