Shadbala is the most important topic in Vedic astrology, it calculates various types of strenth the planet has. There are 6 different types of strength namely:
(1) Sthan Bala (Positional Strength)
(2) Dig Bala (Directional strength)
(3) Kala Bala (Time of the day)
(4) Chesta Bala (Motional Strength)
(5) Naisargik Bala (Permanent Strength)
(6) Drik Bala (Aspect strength)
If the total strength is more then minimum strength we can say the planet position is strong whereas if the total points are less then the minimum requirement then we can say that planet is week.