user7878: I play this kid that does strange things in the game. I thought in this following game that he was using the Pirc defense as Black, when it opened 1.d4 d6 2.e4 Nf6 3.Nc3. Then he goes off with 3...d5. It seems that I get trapped by this kind of (to me) irrational thing. Any advice on how best to proceed?
[FEN ""]
1. d4 d6 2. e4 Nf6 3. Nc3 d5


user7657: He just lost a tempo, taking two moves to get his pawn to d5 when he could have done it in one move.  Losing time is particularly bad in the opening when you could be using it to develop pieces.  You can use your "free" move to give your "e" pawn additional support or advance it to e5 gaining additional space as well as a tempo on his N, which will be forced to move again. Even taking the pawn isn't out of the question, since you're still left with a center pawn and lots of open lines for development.  Don't panic and just make sound moves. 

user7961: 4.e5 looks like the move here, because d6-d5 makes this move possible and because the Nf6 has no good squares.  A few possible lines after 4. e5:
(1) 4...Ne4 5.Nxe4 (other moves like 5.Bd3 or 5.Nce2 should also give White an edge, but 5.Nxe4 looks most principled because Black will struggle to save the pawn on e4) 5...dxe4 6.c3 Bf5 7.Ne2 e6 8.Ng3 Bg6 9.h4 h6 10.h5 Bh7 11.Bc4, and even if Black can somehow hold the pawn on e4 (unlikely), he has a miserable position with a huge space disadvantage and a bad Bishop on h7.  This position is somewhere between very bad to losing for Black.
(2) 4...Nd7 5.Nxd5 and White wins a pawn "with compensation" (i.e., White also has a positional advantage due to his strong center).  Black can play on, but he is already completely lost in a theoretical sense.
(3) 4...Ng8 is obviously miserable, as White has gotten two strong pawn moves (e2-e4-e5) for free, and Black will struggle to develop his Kingside sensibly because both his Be7 and Ng8 want the e7 square.  This position is bad for Black, although it's perhaps not possible to say Black is losing: as someone mentioned above, Black cannot afford to waste so much time in the opening and stands much worse here.

user12873: I actually had a game with a GM a few years ago, which went 1.d4 d6 2.e4 Nf6 3.f3 d5 (I was White). This line is somewhat dubious for Black, but it's playable since after 4.e5 Nfd7, White has essentially wasted a tempo on f3. The pawn is no good there, and a tempo must be spent advancing it further to f4. Nevertheless White still has the better game.
But against 3.Nc3, 3...d5 is just a clear mistake. On 4.e5, 4...Nfd7 can't even be played since it would hang the d5-pawn. In the case of 4...Ne4, 5.Nxe4 dxe4 6.Be3 leaves Black with a seriously weak e4-pawn. Finally, 4...Ng8 wastes too many tempi to give Black a satisfactory game, and he could be getting wiped off the board soon.

user4362: I have never seen this idea before, but it is not as stupid as it looks.
There are basically three options for white:

Play the Veresov, i.e. 4.f3. In that case black will argue that he has the black side of a Caro-Kann-Fantasy variation and that he will at one point play c5 in one move, regaining the tempo lost with d6-d5. 
Play exd5. In that case black will say that he has a Scandinavian defense and that compared to the line 1.e4 d5 2.ed Nf6 3.Nf3 Nxd5 there is no 4.c4 kicking the knight from d5 and establishing a nice space advantage.
Play e5. In that case black will probably play 4...Ne4 and you can try to be tricky with 5.Nce2, trying to catch the knight with f3. Taking the knight directly with 5.Nxe4 is also possible, but there is probably no way to quickly assault the weak pawn on e4. 

I think 4.e5 is the most principled option, but it is no refutation. You'll get a very complicated fight were the most you can hope for is that your opponent has to be more careful than you. 

7878: <p>I play this kid that does strange things in the game. I thought in this following game that he was using the Pirc defense as Black, when it opened <code>1.d4 d6 2.e4 Nf6 3.Nc3</code>. Then he goes off with <code>3...d5</code>. It seems that I get trapped by this kind of (to me) irrational thing. Any advice on how best to proceed?</p>

<pre><code>[FEN ""]
1. d4 d6 2. e4 Nf6 3. Nc3 d5
</code></pre>
 7657: <p>He just lost a tempo, taking two moves to get his pawn to d5 when he could have done it in one move.  Losing time is particularly bad in the opening when you could be using it to develop pieces.  You can use your "free" move to give your "e" pawn additional support or advance it to e5 gaining additional space as well as a tempo on his N, which will be forced to move again. Even taking the pawn isn't out of the question, since you're still left with a center pawn and lots of open lines for development.  Don't panic and just make sound moves. </p>
 7961: <p>4.e5 looks like the move here, because d6-d5 makes this move possible and because the Nf6 has no good squares.  A few possible lines after 4. e5:</p>

<p>(1) 4...Ne4 5.Nxe4 (other moves like 5.Bd3 or 5.Nce2 should also give White an edge, but 5.Nxe4 looks most principled because Black will struggle to save the pawn on e4) 5...dxe4 6.c3 Bf5 7.Ne2 e6 8.Ng3 Bg6 9.h4 h6 10.h5 Bh7 11.Bc4, and even if Black can somehow hold the pawn on e4 (unlikely), he has a miserable position with a huge space disadvantage and a bad Bishop on h7.  This position is somewhere between very bad to losing for Black.</p>

<p>(2) 4...Nd7 5.Nxd5 and White wins a pawn "with compensation" (i.e., White also has a positional advantage due to his strong center).  Black can play on, but he is already completely lost in a theoretical sense.</p>

<p>(3) 4...Ng8 is obviously miserable, as White has gotten two strong pawn moves (e2-e4-e5) for free, and Black will struggle to develop his Kingside sensibly because both his Be7 and Ng8 want the e7 square.  This position is bad for Black, although it's perhaps not possible to say Black is losing: as someone mentioned above, Black cannot afford to waste so much time in the opening and stands much worse here.</p>
 12873: <p>I actually had a game with a GM a few years ago, which went 1.d4 d6 2.e4 Nf6 3.f3 d5 (I was White). This line is somewhat dubious for Black, but it's playable since after 4.e5 Nfd7, White has essentially wasted a tempo on f3. The pawn is no good there, and a tempo must be spent advancing it further to f4. Nevertheless White still has the better game.</p>
<p>But against 3.Nc3, 3...d5 is just a clear mistake. On 4.e5, 4...Nfd7 can't even be played since it would hang the d5-pawn. In the case of 4...Ne4, 5.Nxe4 dxe4 6.Be3 leaves Black with a seriously weak e4-pawn. Finally, 4...Ng8 wastes too many tempi to give Black a satisfactory game, and he could be getting wiped off the board soon.</p>
 4362: <p>I have never seen this idea before, but it is not as stupid as it looks.</p>

<p>There are basically three options for white:</p>

<ul>
<li><p>Play the Veresov, i.e. 4.f3. In that case black will argue that he has the black side of a <a href="http://kenilworthian.blogspot.de/2010/03/caro-kann-defense-fantasy-variation.html" rel="nofollow">Caro-Kann-Fantasy variation</a> and that he will at one point play c5 in one move, regaining the tempo lost with d6-d5. </p></li>
<li><p>Play exd5. In that case black will say that he has a <a href="https://en.wikipedia.org/wiki/Scandinavian_Defense" rel="nofollow">Scandinavian defense</a> and that compared to the line 1.e4 d5 2.ed Nf6 3.Nf3 Nxd5 there is no 4.c4 kicking the knight from d5 and establishing a nice space advantage.</p></li>
<li><p>Play e5. In that case black will probably play 4...Ne4 and you can try to be tricky with 5.Nce2, trying to catch the knight with f3. Taking the knight directly with 5.Nxe4 is also possible, but there is probably no way to quickly assault the weak pawn on e4. </p></li>
</ul>

<p>I think 4.e5 is the most principled option, but it is no refutation. You'll get a very complicated fight were the most you can hope for is that your opponent has to be more careful than you. </p>
