If I start the Xboard engine Spike, it generates an assorted list of evaluations and lines. I suppose that each assessment (- to +) is from the point of view of the color which has to play. So the last one - depending on the countermove - should be the best. So far so good, but why are there different evaluations for apparently the same move, countermove, move ...? Is there a simple rule to find out what continuation is preferable? T.i.a.