user928: What known position has one side with a forced mate in N moves, with N the largest? I came across one with 517 moves using only 7 pieces, so there should be much be larger. (Ignoring the 50-move rule).   
Dont know if this is on-topic here, - but how large can we make N (asymptotically) on an nxn chess-board with any number of pieces and placements?

user672: I think answers to this question fall into 2 categories : problem composition and computer-driven few-pieced endgames' thorough analysis. The second one — to which your discovery belongs — being a tad bit more efficient than the first, that's probably all there is to say about it, if you're about sheer numbers. Art still has a long way to go on this road.
Regarding computer-driven endgames, the longest known so far is 549 moves long.
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928: <p>What known position has one side with a forced mate in N moves, with N the largest? I came across one with 517 moves using only 7 pieces, so there should be much be larger. (Ignoring the 50-move rule).   </p>

<p>Dont know if this is on-topic here, - but how large can we make N (asymptotically) on an nxn chess-board with any number of pieces and placements?</p>
 672: <p>I think answers to this question fall into 2 categories : problem composition and computer-driven few-pieced endgames' thorough analysis. The second one — to which your discovery belongs — being a tad bit more efficient than the first, that's probably all there is to say about it, if you're about sheer numbers. Art still has a long way to go on this road.</p>

<p>Regarding computer-driven endgames, the longest known so far is <a href="http://tb7.chessok.com/articles/Top8DTM_eng" rel="nofollow noreferrer">549 moves long</a>.</p>

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