user-1: In the position below White continues with e4 after, say, Black castles. grunfeld-defense:
[FEN ""]
[StartPly "10"]

1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Nf3 Bg7 5. Qb3 dxc4 6.Qxc4 

Question: How about e3 instead? Is there an outright refutation, or is it just stylistic choice?
I know a couple of QGD lines where after years of practice, people have started to try apparently less aggressive strategies, say by playing e3 and planning for a future e4 rather than an immediate e4 (which makes the game more dynamic and allows quick counterplay). The results have been better with the "slow" moves.
A follow-up: Does the inclusion of Bf4 and then e3 change the evaluation?

user32449: After your position, the most played move (at least by two orders of magnitude) is 6... O-O so I will focus on it only.
The main takeaway is that 7. e4 forbids 7... b6 (controlling the a8-h1 diagonal), but 7. e3 doesn't and black takes advantage of it by playing 7... b6.
If you want some engine statistics, Stockfish 22050407 evaluates

e4 b6 as at least up 200 centipawns (+2) for white with best move e5, so most likely winning for white (WDL ratio ~950 white wins, ~50 draws, =0 black wins).
e3 b6 as 0 centipawns, but black has better play overall.


-1: <p>In the position below White continues with e4 after, say, Black castles. <a href="/questions/tagged/grunfeld-defense" class="post-tag" title="show questions tagged &#39;grunfeld-defense&#39;" rel="tag">grunfeld-defense</a>:</p>
<pre><code>[FEN &quot;&quot;]
[StartPly &quot;10&quot;]

1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Nf3 Bg7 5. Qb3 dxc4 6.Qxc4 
</code></pre>
<p><strong>Question: How about e3 instead? Is there an outright refutation, or is it just stylistic choice?</strong></p>
<p>I know a couple of QGD lines where after years of practice, people have started to try apparently less aggressive strategies, say by playing e3 and planning for a future e4 rather than an immediate e4 (which makes the game more dynamic and allows quick counterplay). The results have been better with the &quot;slow&quot; moves.</p>
<p><strong>A follow-up: Does the inclusion of Bf4 and then e3 change the evaluation?</strong></p>
 32449: <p>After your position, the most played move (at least by two orders of magnitude) is 6... O-O so I will focus on it only.</p>
<p>The main takeaway is that 7. e4 forbids 7... b6 (controlling the a8-h1 diagonal), but 7. e3 doesn't and black takes advantage of it by playing 7... b6.</p>
<p>If you want some engine statistics, Stockfish 22050407 evaluates</p>
<ol start="7">
<li>e4 b6 as at least up 200 centipawns (+2) for white with best move e5, so most likely winning for white (WDL ratio ~950 white wins, ~50 draws, =0 black wins).</li>
<li>e3 b6 as 0 centipawns, but black has better play overall.</li>
</ol>
