Logic behind the concept of temporary enemies
 

Planets in the 2nd, 3rd, 4th, 10th, 11th and 12th sign from a planet are considered "temporary friends" whereas planets in the same sign, 5th, 6th, 7th, 8th and 9th from a planet are considered "temporary enemies".

Some of this is counter-intuitive as you would expect planets in the 12th from a place to be an enemy and planets in the 5th and 9th to be a friend, purely from the nature of of those houses.

And also consider that Jupiter will only aspect it's temporary enemies through it's 5th and 9th special aspect, this also seems counter-intuitive.

What is the logic/reasoning behind considering these placements friendly or unfriendly?

Re: Logic behind the concept of temporary enemies
 

I believe this is one of the many considerations of *strength determination* in a horoscope and makes some sense if visualized as a war-scenario in which planets find themselves arranged in two groups, one group (temporary friends) arranged on the side of one army, whereas the opponent army gets placed in the opposing zone, nominally in the opposing placements. This is unlike the consideration known as the natural (naisargika) relationships which consider a different arrangement from the tatkalika ones.

I have not come across the rationale adopted by the original source (or their precise era, etc when the rules were originally stated presumably verbally followed by the material getting transcribed eventually), so cannot comment on their reasoning for including it as part of the fairly intricate shadbala scheme used in Jyotish.

If you feel uncomfortable in using this relationship parameter, you can try excluding it for your calculations, and see if doing so makes any significant differences in your analyses and interpretations.

Best wishes,