While the primaries formed between the Ascendant and Midheaven to the planets during the lifetime of the person produce notable events, the  great majority of  those formed between planets -  the so-called inter-planetaries – produce few significant events compared to directions of planets to the house cusps.

We begin by considering  the principal  factors that make it difficult to determine what effect a given direction can cause. This leads to a discussion of what factors will determine if in fact a given direction will cause an effect. This requires that we examine the criteria that permit us to differentiate  a significator from a promittor. As Zoltan Mason said, “The great difficulty is to figure out which planet caused the event”, that is which planet is the promittor?

This requires that we determine the factors that describe  the type  of “accident”, the technical expression used  to describe  any type of event. As the significator is the principal factor upon which a prediction depends, its status must be carefully investigated.  It is the subject  of the direction and after determining its meaning, we  consider the promittor, the cause of the effect of the  direction, and on whom the effect principally depends.