title: How to create a logical paper and pencil game like Sudoku?
body: <p>This question is not limited to Sudoku, but may include Kakuro, Hitori, Nurikabe, etc.</p>
  
  <p>I understand the algorithm to <strong>solve</strong> Sudoku and other similar puzzles, but I'm having a hard time figuring out how to <strong>create</strong> them.</p>
  
  <p>Say I want a Sudoku generator (to take the most popular). I guess it needs to work in two steps:</p>
  
  <ol>
  <li>Create a valid solution</li>
  <li>Remove parts of the solution until the desired amount of clues are left.</li>
  </ol>
  
  <p>Creating a solution isn't trivial, it usually works well if you go randomly until you reach the last steps and end up in a deadlock.</p>
  
  <p>Removing some parts of the solution required to be sure to remove only redundant ones, which isn't trivial either.</p>
  
  <p>Is there a generic algorithm to work it out? How can I implement such a thing?</p>
  
  <p>I understand my question is "broad" and that I don't show a lot of what I've got so far (splitting the problem in two), but I don't have any lead to start thinking about the algorithm. I'm not asking for a solution, but rather for hints on how to begin.</p>