user10682: We are installing the Gull engine for some chess enthusiasts in an organization.
We would like to set 6 difficulty levels from beginner to master using depth.
Is there someone who can advice us about which values are the most accurate and progressive for each level?

user10687: You may find this post by the developers of the website https://lichess.org/ helpful.
Although they use Stockfish as the engine, they set the search depths as such (note that they have eight levels of play):

AI level 1: skill 3/20, depth 1, 50ms
AI level 2: skill 6/20, depth 2, 100ms
AI level 3: skill 9/20, depth 3, 150ms
AI level 4: skill 11/20, depth 4, 200ms
AI level 5: skill 14/20, depth 6, 250ms
AI level 6: skill 17/20, depth 8, 300ms
AI level 7: skill 20/20, depth 10, 350ms
AI level 8: skill 20/20, depth 12, 400ms

I have personally played and seen others play against the varying levels. Level 1 is almost joke worthy--the computer may move his queen completely into danger, completely miss checkmates, etc.
On the other hand, level eight is crushing; beating it requires repeated practice over the same line (at least, that is the only way I've seen people beat it).

10682: <p>We are installing the Gull engine for some chess enthusiasts in an organization.
We would like to set 6 difficulty levels from beginner to master using depth.
Is there someone who can advice us about which values are the most accurate and progressive for each level?</p>
 10687: <p>You may find <a href="https://lichess.org/blog/U4mtoEQAAEEAgZRL/strongest-chess-player-ever" rel="nofollow noreferrer">this post</a> by the developers of the website <a href="https://lichess.org/" rel="nofollow noreferrer">https://lichess.org/</a> helpful.</p>

<p>Although they use <a href="http://stockfishchess.org/" rel="nofollow noreferrer">Stockfish</a> as the engine, they set the search depths as such (note that they have eight levels of play):</p>

<ul>
<li>AI level 1: skill 3/20, depth 1, 50ms</li>
<li>AI level 2: skill 6/20, depth 2, 100ms</li>
<li>AI level 3: skill 9/20, depth 3, 150ms</li>
<li>AI level 4: skill 11/20, depth 4, 200ms</li>
<li>AI level 5: skill 14/20, depth 6, 250ms</li>
<li>AI level 6: skill 17/20, depth 8, 300ms</li>
<li>AI level 7: skill 20/20, depth 10, 350ms</li>
<li>AI level 8: skill 20/20, depth 12, 400ms</li>
</ul>

<p>I have personally played and seen others play against the varying levels. Level 1 is almost joke worthy--the computer may move his queen completely into danger, completely miss checkmates, etc.</p>

<p>On the other hand, level eight is crushing; beating it requires repeated practice over the same line (at least, that is the only way I've seen people beat it).</p>
