user24016: I am watching videos about the London system, and one example they use is this game.
[Title "Carlsen-Ghaem, Baku 2016"]
[FEN ""]

1. d4 d5 2. Nf3 Nf6 3. Bf4 e6 4. e3 Bd6 5. Bg3 c5 6. c3 Nc6 7. Nbd2 Bxg3 8. hxg3 Qd6 9. Bb5 Bd7 

after 8. ... Qd6, the guy explaining the video says that Black is preparing to move e5, so White moves 9. Bb5 to avoid that. What is Black's plan with that move?

user13074: My thinking is that Black's long-term problem is being saddled with a bad Bishop, his pawns on white squares limit it's scope so try for Ne7 and hope for the exchange.
If Black allows BxN the White's Ne5 looks strong.
The dilemma for Black set by Carlsen: do I risk castling into the open h file, do I plan to castle Q side or do I wait until White makes his intentions re castling clear?

user15223: With ...e5, Black:

Opens a diagonal for the c8-bishop, and
Fights for central control.

Both of these adhere to chess principles, so planning for ...e5 is a very natural thing for Black.

24016: <p>I am watching videos about the London system, and one example they use is this game.</p>
<pre><code>[Title &quot;Carlsen-Ghaem, Baku 2016&quot;]
[FEN &quot;&quot;]

1. d4 d5 2. Nf3 Nf6 3. Bf4 e6 4. e3 Bd6 5. Bg3 c5 6. c3 Nc6 7. Nbd2 Bxg3 8. hxg3 Qd6 9. Bb5 Bd7 
</code></pre>
<p>after 8. ... Qd6, the guy explaining the video says that Black is preparing to move e5, so White moves 9. Bb5 to avoid that. What is Black's plan with that move?</p>
 13074: <p>My thinking is that Black's long-term problem is being saddled with a bad Bishop, his pawns on white squares limit it's scope so try for Ne7 and hope for the exchange.</p>
<p>If Black allows BxN the White's Ne5 looks strong.</p>
<p>The dilemma for Black set by Carlsen: do I risk castling into the open h file, do I plan to castle Q side or do I wait until White makes his intentions re castling clear?</p>
 15223: <p>With ...e5, Black:</p>
<ol>
<li>Opens a diagonal for the c8-bishop, and</li>
<li>Fights for central control.</li>
</ol>
<p>Both of these adhere to chess principles, so planning for ...e5 is a very natural thing for Black.</p>
