ve backward) to be solved. The
problems with the lower success ratio are chosen first.</p>

<p><img src="Problem-Ratio.gif" width="342" height="58"></p>

<p>The requested ratio is an objective which perhaps cannot be
reached. This occurs for instance when the problem collection has
never been visited.</p>

<hr size="1" color="#C0C0C0">

<h3>Right and wrong move encoding</h3>

<p>There are several ways of coding the right and wrong moves in
a SGF file. <strong>Drago</strong> handles the following cases:</p>
