Persian Firdar (Firdaria) are periods of life that fall under governorship of the planets as chronocrators (givers of life). A medieval technique attributed to the Persians.
Chaldean Firdar differs from Persian that the ruler of the first period is the planet-ruler of a sign on an ascendant, and duration of the first period is reduced proportionally to position of a planet-ruler of an ascendant in this sign.
Vimshottari dasa is a technique of forecasting in Vedic astrology, it is based on a comparison of periods of life of the native with certain planets.
Click a line to see the subperiods.