user27067: I'm looking for a "universal" opening. One example is the King's Indian, which you can play against e4, d4, and several other openings. What other openings, for Black or White, can be played versus most classical openings?

user4418: As white the task is much easier because you make the first move and dictate terms.
You have:



g4 The Grob




f4 Bird's




Nf3 Reti




b3




b4 Sokolosky



As black you are more limited and have to play much more passively to be able to play the same moves against almost any white response.
The Hedgehog where you play to try and reach this kind of position:
 [fen "2r1r1k1/1bqnbppp/pp1ppn2/8/2P1P3/8/PP3PPP/8 b - - 0 1"]

The Hippopotamus which looks like this (Don't mess with the Hippo!):
 [fen "r2qk2r/1bpnnpb1/pp1pp1pp/8/8/8/8/8 b - - 0 1"]


user9179: If you like the King's Indian with black I see no problem with going with the King's Indian Attack with white.
Also, for those who want an opening that fits all black responses the London System seems the way to go.

27067: <p>I'm looking for a &quot;universal&quot; opening. One example is the King's Indian, which you can play against e4, d4, and several other openings. What other openings, for Black or White, can be played versus most classical openings?</p>
 4418: <p>As white the task is much easier because you make the first move and dictate terms.</p>
<p>You have:</p>
<ul>
<li>
<ol>
<li>g4 The Grob</li>
</ol>
</li>
<li>
<ol>
<li>f4 Bird's</li>
</ol>
</li>
<li>
<ol>
<li>Nf3 Reti</li>
</ol>
</li>
<li>
<ol>
<li>b3</li>
</ol>
</li>
<li>
<ol>
<li>b4 Sokolosky</li>
</ol>
</li>
</ul>
<p>As black you are more limited and have to play much more passively to be able to play the same moves against almost any white response.</p>
<p>The <a href="https://en.wikipedia.org/wiki/Hedgehog_(chess)" rel="nofollow noreferrer">Hedgehog</a> where you play to try and reach this kind of position:</p>
<pre><code> [fen &quot;2r1r1k1/1bqnbppp/pp1ppn2/8/2P1P3/8/PP3PPP/8 b - - 0 1&quot;]
</code></pre>
<p>The Hippopotamus which looks like this (<a href="https://www.youtube.com/watch?v=pdAthyBbN7c&amp;ab_channel=EricRosen" rel="nofollow noreferrer">Don't mess with the Hippo!</a>):</p>
<pre><code> [fen &quot;r2qk2r/1bpnnpb1/pp1pp1pp/8/8/8/8/8 b - - 0 1&quot;]
</code></pre>
 9179: <p>If you like the King's Indian with black I see no problem with going with the <a href="https://en.wikipedia.org/wiki/King%27s_Indian_Attack" rel="nofollow noreferrer">King's Indian Attack</a> with white.</p>
<p>Also, for those who want an opening that fits all black responses the <a href="https://en.wikipedia.org/wiki/London_System" rel="nofollow noreferrer">London System</a> seems the way to go.</p>
