user32155: I am currently learning Sicilian Svenshnikov. Today, I came across a new line with Nd5 variation. First, we move a4 to kick the white knight and then play a5. I couldn't quite understand the point of this move as it gives back white the b5 square for its knight again. So what was the point of playing a5?
Here's the position for it:
[FEN ""]
[Startply "27"]

1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Nd5 Nxd5 8. exd5 Nb8 9. a4 Be7 10. Be2 O-O 11. O-O Nd7 12. Bd2 a6 13. Na3 a5


user4418: 
So what was the point of playing a5?

It is a prophylactic move. It takes the square away from White who was planning to play a5 and take control of the key b6 square in Black's position. Sure, Black could try playing b6 but after the exchange of pawns on b6 black would be left with a weak isolated a pawn.

32155: <p>I am currently learning Sicilian Svenshnikov. Today, I came across a new line with Nd5 variation. First, we move a4 to kick the white knight and then play a5. I couldn't quite understand the point of this move as it gives back white the b5 square for its knight again. So what was the point of playing a5?</p>
<p>Here's the position for it:</p>
<pre><code>[FEN &quot;&quot;]
[Startply &quot;27&quot;]

1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Nd5 Nxd5 8. exd5 Nb8 9. a4 Be7 10. Be2 O-O 11. O-O Nd7 12. Bd2 a6 13. Na3 a5
</code></pre>
 4418: <blockquote>
<p>So what was the point of playing a5?</p>
</blockquote>
<p>It is a prophylactic move. It takes the square away from White who was planning to play a5 and take control of the key b6 square in Black's position. Sure, Black could try playing b6 but after the exchange of pawns on b6 black would be left with a weak isolated a pawn.</p>
