user23699: 4...O-O followed by 6...Ne8!? is a popular line in the f3 Nimzo at master level, but I'm still struggling to understand why it's played.
[FEN ""]
1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.f3 O-O 5.a3 Bxc3 6.bxc3 Ne8!?

In this video, Caleb Denby seems to imply the main reason is Black wants to go after the c4-pawn with a typical Nc6-Na5 / b6-Ba6 plan, but wants to stop an eventual pin with Bg5 that could be annoying for Black and "force him to make concessions in the center." But why not just throw in the move ...h6 at some point instead? eg.
[FEN ""]
1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. f3 O-O 5. a3 Bxc3+ 6. bxc3 c5 7. e4 d6 8. Bd3 Nc6 9. Ne2 h6

To me, it seems pretty bizarre to use a full move to undevelop your knight to a bad square and potentially let White Greek gift you in the future, in anticipation of a move that White isn't even likely to play for another 3 turns.

user14202: 6...Ne8 and 6...d5 are the main moves played followed by 6...Nh5 and 6...d6
The move ...h6 can seriously weaken the b1-h7 diagonal.
Going down the main line might help explain what this Knight is doing on e8:
6...Ne8
7.e4 b6
8.Bd3 Ba6
9.Nh3 Nc6
10.0-0 Na5
11.Qe2 c5
12.e5 f6

From this diagram you can imagine if 6...h6 was played instead.  Once White gets e4-e5 in the b1-h7 diagonal is very weak.
So, 6...Ne8 is kind of a rope-a-dope move.  It free's the f-pawn, opens the queen's view, and avoids e4-e5 with tempo.

23699: <p>4...O-O followed by 6...Ne8!? is a popular line in the f3 Nimzo at master level, but I'm still struggling to understand why it's played.</p>
<pre><code>[FEN &quot;&quot;]
1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.f3 O-O 5.a3 Bxc3 6.bxc3 Ne8!?
</code></pre>
<p>In <a href="https://www.youtube.com/watch?v=zf9vaqXrYvM" rel="noreferrer">this video</a>, Caleb Denby seems to imply the main reason is Black wants to go after the c4-pawn with a typical Nc6-Na5 / b6-Ba6 plan, but wants to stop an eventual pin with Bg5 that could be annoying for Black and &quot;force him to make concessions in the center.&quot; But why not just throw in the move ...h6 at some point instead? eg.</p>
<pre><code>[FEN &quot;&quot;]
1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. f3 O-O 5. a3 Bxc3+ 6. bxc3 c5 7. e4 d6 8. Bd3 Nc6 9. Ne2 h6
</code></pre>
<p>To me, it seems pretty bizarre to use a full move to undevelop your knight to a bad square and potentially let White Greek gift you in the future, in anticipation of a move that White isn't even likely to play for another 3 turns.</p>
 14202: <p>6...Ne8 and 6...d5 are the main moves played followed by 6...Nh5 and 6...d6</p>
<p>The move ...h6 can seriously weaken the b1-h7 diagonal.</p>
<p>Going down the main line might help explain what this Knight is doing on e8:
6...Ne8</p>
<p>7.e4 b6</p>
<p>8.Bd3 Ba6</p>
<p>9.Nh3 Nc6</p>
<p>10.0-0 Na5</p>
<p>11.Qe2 c5</p>
<p>12.e5 f6</p>
<p><a href="https://i.stack.imgur.com/Ltb2P.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Ltb2P.png" alt="enter image description here" /></a></p>
<p>From this diagram you can imagine if 6...h6 was played instead.  Once White gets e4-e5 in the b1-h7 diagonal is very weak.</p>
<p>So, 6...Ne8 is kind of a rope-a-dope move.  It free's the f-pawn, opens the queen's view, and avoids e4-e5 with tempo.</p>
