user32822: [fen "rn3rk1/pp3ppp/3b2q1/2p1p3/1PP3b1/3P1N2/P3BPPP/1RBQR1K1 w - - 1 13"]

According to me, b5 is a pretty okay option, but according to Stockfish 10+ WASM, (Lichess) the advantage drops from +3.7 to +1.6. Why is this? Is it because it allows a3 and the potential opening up of the rook? But can’t I just go b6 in response (somehow, two innocuous pawn moves transform it to -0.6)? Lichess tells me it is a BLUNDER. WHY?
Why is bxc5 so good? According to me, after Bxc5, Black’s dark squared bishop is in an extremely active and attacking square, also pinning my f2 pawn to the king.

user-1: I think that even if it was not for the e5 weakness and the tactics, b5 was still bad. Because you close lines rather then open them for your queenside game. It will take ages to push the a pawn and create tension again and exchange pawns -- if at all possible. The point of b4 is to exchange pawns and open the b file. As simple as that!

user4418: bxc5 wins a pawn on the spot. After Bxc5 white replies Nxe5 forking queen and bishop and any pressure black had on the kingside is gone. With the bishop attacked 3 times (by knight, bishop and queen) black is forced to play Bxe2.
Add to that the fact that the b7 pawn is also en prise although white has to bear in mind Bb6 cutting off the rook's retreat.
[fen "rn3rk1/pp3ppp/3b2q1/2p1p3/1PP3b1/3P1N2/P3BPPP/1RBQR1K1 w - - 1 1"]

1. bxc5 Bxc5 2. Nxe5 Bxe2 3. Rxe2


32822: <pre><code>[fen &quot;rn3rk1/pp3ppp/3b2q1/2p1p3/1PP3b1/3P1N2/P3BPPP/1RBQR1K1 w - - 1 13&quot;]
</code></pre>
<p>According to me, b5 is a pretty okay option, but according to Stockfish 10+ WASM, (Lichess) the advantage drops from +3.7 to +1.6. Why is this? Is it because it allows a3 and the potential opening up of the rook? But can’t I just go b6 in response (somehow, two innocuous pawn moves transform it to -0.6)? Lichess tells me it is a BLUNDER. WHY?</p>
<p>Why is bxc5 so good? According to me, after Bxc5, Black’s dark squared bishop is in an extremely active and attacking square, also pinning my f2 pawn to the king.</p>
 -1: <p>I think that even if it was not for the e5 weakness and the tactics, b5 was still bad. Because you close lines rather then open them for your queenside game. It will take ages to push the a pawn and create tension again and exchange pawns -- if at all possible. The point of b4 is to exchange pawns and open the b file. As simple as that!</p>
 4418: <p>bxc5 wins a pawn on the spot. After Bxc5 white replies Nxe5 forking queen and bishop and any pressure black had on the kingside is gone. With the bishop attacked 3 times (by knight, bishop and queen) black is forced to play Bxe2.</p>
<p>Add to that the fact that the b7 pawn is also en prise although white has to bear in mind Bb6 cutting off the rook's retreat.</p>
<pre><code>[fen &quot;rn3rk1/pp3ppp/3b2q1/2p1p3/1PP3b1/3P1N2/P3BPPP/1RBQR1K1 w - - 1 1&quot;]

1. bxc5 Bxc5 2. Nxe5 Bxe2 3. Rxe2
</code></pre>
