user19322: I'm looking for an iPhone app that will allow me to set up a chess problem and work out its solution.  I've seen apps that present me with a battery of chess problems but don't allow me to set up my own.  I've also seen apps that allow me to play chess starting from the opening position.  But I haven't seen one that will allow me to configure the board as I choose.  Admittedly I haven't tried every existing iPhone app but none of the ones I've looked at allow this.

user18769: Mastersoft makes a Chess app, with similar modes to Glorfindel’s answer.
I do not remember if it was free. 

user7297: The only chess app on my iPhone is Stockfish, and it has a menu option Game -> Edit position where you can set up your own board. You'd also have to change the Level/Game mode to 'Two player'.

It's a free app.

19322: <p>I'm looking for an iPhone app that will allow me to set up a chess problem and work out its solution.  I've seen apps that present me with a battery of chess problems but don't allow me to set up my own.  I've also seen apps that allow me to play chess starting from the opening position.  But I haven't seen one that will allow me to configure the board as I choose.  Admittedly I haven't tried every existing iPhone app but none of the ones I've looked at allow this.</p>
 18769: <p>Mastersoft makes a <a href="https://apps.apple.com/us/app/chess-pro-ultimate-edition/id561435724" rel="nofollow noreferrer">Chess</a> app, with similar modes to Glorfindel’s answer.</p>

<p>I do not remember if it was free. </p>
 7297: <p>The only chess app on my iPhone is <a href="https://apps.apple.com/us/app/stockfish-chess/id305558605" rel="nofollow noreferrer">Stockfish</a>, and it has a menu option Game -> Edit position where you can set up your own board. You'd also have to change the Level/Game mode to 'Two player'.</p>

<p><a href="https://i.stack.imgur.com/piN3g.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/piN3g.jpg" width="300"></a></p>

<p>It's a free app.</p>
