Correctly classifying all directions of the edges in a tree would provide us with root. Such a classification would be one method to obtain a root, but would have a caveat. If only a few edges would be classified wrongly, the resulting contradiction could be resolvable in more than one equally probable way. Instead of looking at single edges or the complete tree, we focus on paths, namely all paths from one leaf to another leaf. The situation we start from is thus an unrooted tree (UT) with exactly one covertly underlying rooted tree (RT), the gold standard. What we can distinguish in the UT are only leafs and internodes. For any leaf, we suppose that there is at least one fellow leaf which is so remote that their latest common ancestor is root. Furthermore we do know that any shortest path from leaf to leaf in the UT must pass through the latest common ancestor of both leafs. We want to denote it by <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#424242)">◇</hi> l<hi xmlns="http://www.tei-c.org/ns/1.0" rend="sub">i</hi>, l<hi xmlns="http://www.tei-c.org/ns/1.0" rend="sub">j</hi> but we initially don't know which of the nodes on the path in the UT it is. <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#424242)">◇</hi> is pivotal for directionality in the RT: all directions of edges towards the two leafs point away from it. Thus, traversing the path by edges from one leaf to the other, direction changes in the RT when passing <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#424242)">◇</hi>. If, as we supposed, for each leaf there is at least one other leaf for which <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#424242)">◇</hi> is root, then, comparing all leaf-leaf paths starting in a leaf l<hi xmlns="http://www.tei-c.org/ns/1.0" rend="sub">1</hi>, the <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#424242)">◇</hi> most distant from l<hi xmlns="http://www.tei-c.org/ns/1.0" rend="sub">1</hi> must coincide with root since there can be no later common ancestor in the RT. Moreover, all leafs should converge on the same node as the most distant <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#424242)">◇</hi>. Thus, if one could detect that node on any leaf-leaf path which is pivotal for direction, one would know for each such path the direction change point <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#424242)">◇</hi> and in consequence root. Detecting the most probable point of direction change on a path may be easier and lead to less contradictions than classifying each edge for direction since the path itself provides context. However, there is a case we have so far not taken into account: the case that RT is a planted tree. In that case, the highest direction change convergence point (HDCCP) would be the first node in the RT that has more than one child. Also, there would be one leaf, on the path to which all other leaves do not detect any direction change, which our algorithm tracks. For a graphical explanation in case root is internal, see Figure 1.