It is very hard to answer this question without White's next move after you played
d5. I bet he tried something like
3.Nf3 or even
3.d3 would not surprise me.
You see, the move
2.Nc3 is not bad-it follows all the opening rules, and is used only to transpose from one opening into another or to dodge certain variations that are unpleasant for White.
In my opinion, I assume that White did not want to play main lines of the French defense so he tried to trick you to transpose into another opening or another line, the one you do not know.
This is especially useful in blitz games. Your move-
2.d5-is the best move.
Never fool around with transpositions when you play blitz, always spend the least amount of time possible on openings. Quality blitz games are won in the middle game or by the expiration of thinking time, not in the opening.
The main point of
2.Nc3 is that it can not be refuted, and it can not give White a bad position.
White tries to force you to waste important thinking time on the opening trying to refute this move. You could play
2.c5 here but why? After
c5 you get Sicilian defense which is not your repertoire against
1.e4 is it? Therefore, White would achieve his goal-he would transpose into opening you do not know-because if you intended to play the Sicilian defense at the first place you would respond with
1.c5 not with
2.Nf6 he can dodge the French defense by playing
3.e5! which might give him a slight opening advantage. If
2.Nc6 with the idea to play
e5 and transpose into favorable version of the Italian game then
3.d4 transposes into some sort of Nimzovich defense and you are out of your opening in both cases.
2.Bb4 White can now go for
3.Nge2!? with events developing something like this:
1.e4 e6 2.Nc3 Bb4 3.Nge2 d5 4.a3 Ba5 5.d4 dxe4
This position is known in the Winawer French defense-it is coded as
C15 in the
ECO and the above is the sideline. This variation is not played with bishop on
a5, and being unable to find any theoretical resource that mentions this position in Winawer line I must conclude that the move
Ba5 in the regular line is bad-which is precisely the goal of White's altered move order. In the normal Winawer things would go like this:
1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.Nge2 dxe4 5.a3 Bxc3+ ( 5...Be7!? )
We can list other moves or possibilities for Black after White plays
2.Nc3, but let us keep this post short and answer your question:
- e4 e6 2. Nc3 - how should Black respond?
Again, I consider your
d5 to be the strongest move-both for theoretical and psychological/practical reasons explained below:
Do not experiment with transpositions or you may end up in a position that will very likely be unfavorable for you. You can break this rule only if you are 100% sure that transposition can benefit you. If not then decline it by staying in your opening. Most of the time this is the best choice to make and the most unpleasant one for the side trying to trick you.
If you have further questions leave a comment and I will reply.