user19921: My chess rating is somewhere between 400 and 500 and I have a lot of trouble countering the Scandinavian Defense. My first move is usually e4 but when my opponent uses the Scandinavian Defense (d5), I have a hard time countering that. I heard from everyone that only beginners do it for a reason but I can't exactly figure out why nobody else would use that defense. I am curious if you know an aggressive counter to the Scandinavian defense.

user14202: You are correct to seek an aggressive line since at this stage in your chess development you should be going for the throat.
Here is a suggested line:
1.e4 d5
2.d4 dxe4
3.f3 or Bc4
[EDIT]  3.Nc3 is most common, then the ideas of f3 or Bc4.
Seeking fast development.  You can target f7...

user27648: At your elo opponents are not really prepared with theory so you can surprise them with the following gambit lines :)

You can surprise the casual Scandi player with Mieses gambit that goes: 1. e4-d5 2. exd5 Qxd5 3. Nc3 Qa5 4. b4 with idea of opening the b-file and using the rook to apply pressure and develop with tempo

You can transposition into Reti/Tennison gambit after: 1.e4-d5 2. Nf3 dxe4 3. Ng5 which has very deadly trap if your opponent is not prepared



user18809: If you are having trouble with it, maybe you need to slow down the aggression!
My advice is to play 2.e5. It is theoretically a "bad" move because it allows your opponent to play an improved Caro-Kann or French. But at your skill level, nobody who goes for the Scandinavian will know anything about how to play those!

user12629: 
I heard from everyone that only beginners do it for a reason but I can't exactly figure out why nobody else would use that defense.

It's not true that nobody but beginners use the Scandinavian - I use it, and my rating is in the 1700s.  The opening is, however, somewhat rare; I've only seen it about 4% of the time when I've played 1.e4 in tournament games. Some beginners perhaps like this opening because it gets their queen out early. But this is actually a bad thing for Black, not a good thing. 
As White, one good idea is to make that queen your target. This game is the fastest I've lost playing the Scandinavian, and I lose when my opponent (rated 2042) traps my queen:
[FEN ""]
1.e4 d5 2.exd5 Qxd5 3.Nf3 Qa5 4.Be2 Nf6 5.O-O Bf5 6.d4 c6 7.c4 Nbd7 8.Nc3 e6 9.Bf4 Be7 10.a3 c5 11.Nb5 O-O 12.dxc5 a6 13.Bc7

And here's a game where a beginner (rated 535) tries the Scandinavian against me. Notice how, when possible, I attack his queen with moves that also develop my pieces.
[FEN ""]
1.e4 d5 2.exd5 Qxd5 3.Nc3 {I attack his queen. So far this is the mainline.} Qd4 {This is where we deviate from the mainline Scandinavian. This isn't the best square for his queen.} 4.Nf3 {I attack his queen again.} Qb6 5.Bc4 {I develop another piece. I don't attack his queen with Nd5 or Na4 because that wouldn't help me develop.} Nf6 6.O-O Qd6 {He moves his queen again. His plan is probably to trade off my f3 knight with Bg4 and Bxf3, and then play Ng4 to threaten Qxh2#.} 7.h3 {To prevent his plan. It wouldn't work, but Bg4 is annoying so I prevent it.} Nh5 {Moving his knight again and putting it on the edge of the board. That's usually not a good idea.} 8.Re1 {Activating my rook. It's not the strongest move I could have played. Ng5, attacking f7 and discovering an attack on his knight, was better.} Qg6 {Moving his queen yet again! We're on move 8, and he's moved his queen 5 times. His threat is Bxh3, and I can't play gxh3 because the pawn is pinned by the queen.} 9.Ne5 {Threatening his queen again. He can't play Bxh3 if his queen isn't safe. This also threatens his f7 pawn.} Qg5 {Still threatening Bxh3.} 10.d4 {A discovered attack on his queen. Perhaps I should have just played Bxf7+ now, but this also works.} Nf4 {Blocking the attack on his queen and threatening Qxg2#.} 11.Bxf4 {I have to do something about his checkmate threat.} Qxf4 {Eleven moves in, and his queen is his only piece that isn't on its starting square, while my army is just about fully developed. It's time for me to attack.} 12.Bxf7+ Kd8 13.Bd5 {Threatens Nf7+ forking his king and rook.} Qg5 {Trying to set up Bxh3 again, but it just makes my impending fork worse.} 14.Nf7+ {King-queen fork.} Ke8 15.Nxg5 h6 {From here I have a forced mate.} 16.Qh5+ Kd8 17.Nf7+ Kd7 18.Be6+ Kc6 19.Qc5# 1-0 


19921: <p>My chess rating is somewhere between 400 and 500 and I have a lot of trouble countering the Scandinavian Defense. My first move is usually e4 but when my opponent uses the Scandinavian Defense (d5), I have a hard time countering that. I heard from everyone that only beginners do it for a reason but I can't exactly figure out why nobody else would use that defense. I am curious if you know an aggressive counter to the Scandinavian defense.</p>
 14202: <p>You are correct to seek an aggressive line since at this stage in your chess development you should be going for the throat.</p>

<p>Here is a suggested line:</p>

<p>1.e4 d5</p>

<p>2.d4 dxe4</p>

<p>3.f3 or Bc4
[EDIT]  3.Nc3 is most common, then the ideas of f3 or Bc4.</p>

<p>Seeking fast development.  You can target f7...</p>
 27648: <p>At your elo opponents are not really prepared with theory so you can surprise them with the following gambit lines :)</p>
<ol>
<li><p>You can surprise the casual Scandi player with Mieses gambit that goes: 1. e4-d5 2. exd5 Qxd5 3. Nc3 Qa5 4. b4 with idea of opening the b-file and using the rook to apply pressure and develop with tempo</p>
</li>
<li><p>You can transposition into Reti/Tennison gambit after: 1.e4-d5 2. Nf3 dxe4 3. Ng5 which has very deadly trap if your opponent is not prepared</p>
</li>
</ol>
 18809: <p>If you are having trouble with it, maybe you need to slow down the aggression!</p>

<p>My advice is to play 2.e5. It is theoretically a "bad" move because it allows your opponent to play an improved Caro-Kann or French. But at your skill level, nobody who goes for the Scandinavian will know anything about how to play those!</p>
 12629: <blockquote>
  <p>I heard from everyone that only beginners do it for a reason but I can't exactly figure out why nobody else would use that defense.</p>
</blockquote>

<p>It's not true that nobody but beginners use the Scandinavian - I use it, and my rating is in the 1700s.  The opening is, however, somewhat rare; I've only seen it about 4% of the time when I've played 1.e4 in tournament games. Some beginners perhaps like this opening because it gets their queen out early. But this is actually a <em>bad</em> thing for Black, not a good thing. </p>

<p>As White, one good idea is to make that queen your target. This game is the fastest I've lost playing the Scandinavian, and I lose when my opponent (rated 2042) traps my queen:</p>

<pre><code>[FEN ""]
1.e4 d5 2.exd5 Qxd5 3.Nf3 Qa5 4.Be2 Nf6 5.O-O Bf5 6.d4 c6 7.c4 Nbd7 8.Nc3 e6 9.Bf4 Be7 10.a3 c5 11.Nb5 O-O 12.dxc5 a6 13.Bc7
</code></pre>

<p>And here's a game where a beginner (rated 535) tries the Scandinavian against me. Notice how, when possible, I attack his queen with moves that also develop my pieces.</p>

<pre><code>[FEN ""]
1.e4 d5 2.exd5 Qxd5 3.Nc3 {I attack his queen. So far this is the mainline.} Qd4 {This is where we deviate from the mainline Scandinavian. This isn't the best square for his queen.} 4.Nf3 {I attack his queen again.} Qb6 5.Bc4 {I develop another piece. I don't attack his queen with Nd5 or Na4 because that wouldn't help me develop.} Nf6 6.O-O Qd6 {He moves his queen again. His plan is probably to trade off my f3 knight with Bg4 and Bxf3, and then play Ng4 to threaten Qxh2#.} 7.h3 {To prevent his plan. It wouldn't work, but Bg4 is annoying so I prevent it.} Nh5 {Moving his knight again and putting it on the edge of the board. That's usually not a good idea.} 8.Re1 {Activating my rook. It's not the strongest move I could have played. Ng5, attacking f7 and discovering an attack on his knight, was better.} Qg6 {Moving his queen yet again! We're on move 8, and he's moved his queen 5 times. His threat is Bxh3, and I can't play gxh3 because the pawn is pinned by the queen.} 9.Ne5 {Threatening his queen again. He can't play Bxh3 if his queen isn't safe. This also threatens his f7 pawn.} Qg5 {Still threatening Bxh3.} 10.d4 {A discovered attack on his queen. Perhaps I should have just played Bxf7+ now, but this also works.} Nf4 {Blocking the attack on his queen and threatening Qxg2#.} 11.Bxf4 {I have to do something about his checkmate threat.} Qxf4 {Eleven moves in, and his queen is his only piece that isn't on its starting square, while my army is just about fully developed. It's time for me to attack.} 12.Bxf7+ Kd8 13.Bd5 {Threatens Nf7+ forking his king and rook.} Qg5 {Trying to set up Bxh3 again, but it just makes my impending fork worse.} 14.Nf7+ {King-queen fork.} Ke8 15.Nxg5 h6 {From here I have a forced mate.} 16.Qh5+ Kd8 17.Nf7+ Kd7 18.Be6+ Kc6 19.Qc5# 1-0 
</code></pre>
