user24709: The following position has only eight pieces on the board with Black to move, but it is very tricky. I started trials with my modest means (Houdini 6.02) and White won 3/3 times, but after very complicated lines. I went deep in one case at d= 31/126. Is the ending really won for White?
[FEN "1r6/8/1P1Q2k1/K2P4/N7/3q4/8/8 b - - 0 0"]


user8860: Did Houdini use the 6-man databases?  How did the first few moves go?
If Houdini could find nothing better for White than taking the Rook
then it's a draw (given that White's pawns are moving down
as stated in the comments).
Wherever Black moves the King, the continuation Qxb8 Qxd5+
yields a database draw (presumably by perpetual check),
and the same is true if White first checks on c7 or e5
and plays Qxb8 after Black returns to the sixth rank or goes to h4/g4.

24709: <p>The following position has only eight pieces on the board with Black to move, but it is very tricky. I started trials with my modest means (Houdini 6.02) and White won 3/3 times, but after very complicated lines. I went deep in one case at d= 31/126. Is the ending really won for White?</p>
<pre><code>[FEN &quot;1r6/8/1P1Q2k1/K2P4/N7/3q4/8/8 b - - 0 0&quot;]
</code></pre>
 8860: <p>Did Houdini use the 6-man databases?  How did the first few moves go?</p>
<p>If Houdini could find nothing better for White than taking the Rook
then it's a draw (given that White's pawns are moving down
as stated in the comments).
Wherever Black moves the King, the continuation Qxb8 Qxd5+
yields a database draw (presumably by perpetual check),
and the same is true if White first checks on c7 or e5
and plays Qxb8 after Black returns to the sixth rank or goes to h4/g4.</p>
