user109: What is the best defense as white against the Grunfeld Defense?
I have been playing the Blackmar-Diemer Gambit over and over again, I suspect some opponents notice this, and open up with 1... Nf6, so this gets me off guard.  I usually try to continue the Blackmar-Diemer Gambit, but black normally goes a different route.

user70: Try this link.  This will give you enough search words to find additional information about variations you might explore.  Ultimately, you'll have to decide what's best for you.  If there were a 'best' move, chances are 1... Nf6 would be a blunder.

user-1: First off, 1...Nf6 against 1. d4 is not the Gruenfeld Defense: this opening is defined by an order of moves 3 deep. See the Wikipedia page.
In your case after 1. d4 Nf6 simply play 2. Nc3 and you will be well on your way to getting a Blackmar-Diemer, because if Black doesn't play 2...d5 you will play 3. e4 and you will get your pawn to e4 without having to gambit it: almost like an improved Blackmar-Diemer.
But if Black plays 2...d5 in response to 2. Nc3 then 3. e4 is the Blackmar-Diemer, after 3...dxe4 4. f3, just via a different move order (a "transposition").  See Wikipedia's page for the Blackmar-Diemer.

109: <p>What is the best defense as white against the Grunfeld Defense?</p>

<p>I have been playing the Blackmar-Diemer Gambit over and over again, I suspect some opponents notice this, and open up with <code>1... Nf6</code>, so this gets me off guard.  I usually try to continue the Blackmar-Diemer Gambit, but black normally goes a different route.</p>
 70: <p><a href="http://en.wikibooks.org/wiki/Chess_Opening_Theory/1._d4/1...Nf6" rel="nofollow">Try this link</a>.  This will give you enough search words to find additional information about variations you might explore.  Ultimately, you'll have to decide what's best for you.  If there were a 'best' move, chances are <code>1... Nf6</code> would be a blunder.</p>
 -1: <p>First off, <code>1...Nf6</code> against <code>1. d4</code> is <em>not</em> the Gruenfeld Defense: this opening is defined by an order of moves 3 deep. See the <a href="http://en.wikipedia.org/wiki/Gr%C3%BCnfeld_Defence" rel="nofollow">Wikipedia page</a>.</p>

<p>In your case after <code>1. d4 Nf6</code> simply play <code>2. Nc3</code> and you will be well on your way to getting a Blackmar-Diemer, because if Black doesn't play <code>2...d5</code> you will play <code>3. e4</code> and you will get your pawn to e4 without having to gambit it: almost like an improved Blackmar-Diemer.</p>

<p>But if Black plays <code>2...d5</code> in response to <code>2. Nc3</code> then <code>3. e4</code> <em>is</em> the Blackmar-Diemer, after <code>3...dxe4 4. f3</code>, just via a different move order (a "transposition").  See Wikipedia's page for the <a href="http://en.wikipedia.org/wiki/Blackmar%E2%80%93Diemer_Gambit" rel="nofollow">Blackmar-Diemer</a>.</p>
