user33532: I found two chess puzzles on chessvariants.com, Queens's Quadrille and Hippodrome.
I'm thinking of creating random Queen's Quadrille and Hippodrome puzzles with a computer program.
My question is can I always be sure that a randomly generated Queen's Quadrille or Hippodrome puzzle is solvable?
Should I additionally check if it is solvable after generating a random puzzle?

user16650: Are you asking whether all Queen's Quadrille and Hippodrome problems are solvable? They are not. There is a discussion on the Hippodrome page which you link to. Here is an example of a starting position which is valid both for Queen's Quadrille and for Hippodrome, and where no moves are available:
        5bbQ/4BRrB/4krRK/4NNnn/8/8/8/8 w - - 0 1

Perhaps you could consider a version of Hippodrome where the player gets to choose which of the 12 non-knight pieces is removed. Then it seems more plausible that all positions are solvable.

33532: <p>I found two chess puzzles on <a href="https://www.chessvariants.com" rel="nofollow noreferrer">chessvariants.com</a>, <a href="https://www.chessvariants.com/solitaire.dir/quadrille.html" rel="nofollow noreferrer">Queens's Quadrille</a> and <a href="https://www.chessvariants.com/solitaire.dir/hippodrome.html" rel="nofollow noreferrer">Hippodrome</a>.</p>
<p>I'm thinking of creating <strong>random</strong> Queen's Quadrille and Hippodrome puzzles with a computer program.</p>
<p>My question is can I always be sure that a randomly generated Queen's Quadrille or Hippodrome puzzle is solvable?</p>
<p>Should I additionally check if it is solvable after generating a random puzzle?</p>
 16650: <p>Are you asking whether all Queen's Quadrille and Hippodrome problems are solvable? They are not. There is a discussion on the Hippodrome page which you link to. Here is an example of a starting position which is valid both for Queen's Quadrille and for Hippodrome, and where no moves are available:</p>
<pre><code>        5bbQ/4BRrB/4krRK/4NNnn/8/8/8/8 w - - 0 1
</code></pre>
<p>Perhaps you could consider a version of Hippodrome where the player gets to choose which of the 12 non-knight pieces is removed. Then it seems more plausible that all positions are solvable.</p>
