An infrequent condition called “planetary war” (Graha Yuddha) also affects the strength or weakness of the planets. When planets get within 1º absolute distance from each other, they fight. This only applies to the five real planets. The luminaries and nodes do not resort to war at any time.
Who wins the war? Venus never loses. That is the first rule. Why? Because she is by far brighter and stronger than any other starry planet. If Venus is not involved, the planet with a more northern declination wins the war. Why? He with the “higher ground” can win.
What happens after the war? The victor gets stronger and the loser gets weaker. How much stronger or weaker? Figure out the difference between the sixfold strength of both planets partaking in the war. Deduct that difference from the strength of the loser, and add it to the strength of the victor.