Dasa gives a system whereby we see the results which impact the native in a time period. Each Dasha is controlled by one planet. It is the disposition and relationship of this planet, that the promised events are reflected. The results which a planet promises in its Dasa has to be studied by a careful analysis of the planet.

A Vedic or Hindu Dasa system is one of the unique methodologies developed by the ancient Seers. The various Dasa studies indicate certain predispositions or tendencies in human life, which some times, are so clear that they become virtual certainties. Experience is the great test, and had not the experience proved to the truth of the deductions of various Dasas methods.

The Vimshottari Dasha is a 120 year cycle of planetary position based on the position of Moon in one of the lunar mansions called Nakshatras.

We have started the book explaining various Dasas. The first basic principles have been explained at length. In the next part we go in details, discussing the strength of the planet depending upon position of planets, lordship and various rules that modify the strength. Each Dasa and its predictive aspect are explained in details. It takes into consideration the sign in which the planet is posited. It also explains the effect of directional strength, state of the planet and the divisional strength. This will enable the reader to make an overall assessment of the planet whose Dasa is being analyzed for a native.

The next part dwells with the rules that have to be followed while taking the impact of Sub Period in the major period (Dasa) of the planet. We have in details discussed factors that strengthen or weaken the result which is promised. Further the impact of other vectors, like the transit and strength have been explained.

The Principles of predictions are three- Logic, Sense, and Experience, but the main principles of operations are four -The Planets, the Constellations and the positions of all these in respect of one another, and the Native's backdrop.

"During the PERIODS of a planet- As the general effects of the horoscope is derived from the configurations and conditions of all the planets, taken as natural significators for the whole life, so, in judging of the effects of any period of the life, attention must be paid to the condition (by position and configuration) of the planet ruling that period as determined by the Dasa calculation, i.e., the dividing of time (the life-period) into its periodical sub divisions i.e. periods, sub-periods, and sub-sub-periods."

Excerpt From
Encyclopedia of Vedic Astrology: Dasa Systems
Shanker Adawal