In the Jyotish/Vedic Astrological system, a Dasha is essentially a chapter of life. Specifically the main Dasha system is Vimshotarri. It comes from the Lord of the Nakshatra of your Moon. For example my Moon is in Leo in the Uttara Phalguni Nakshatra which is ruled by Sun . So my first Dasha from birth is Sun. From that reference point the rest of my dashas come from that starting point. The order of a Dasha is as follows; Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury, Ketu, and Venus. Each planetary Dasha has its own time-span. For example the Rahu Dasha is 18 years. The Dashas are important because they show when things activate in your chart for good or for bad. In Jyotish, one of the major prediction techniques is through the system of Yogas, which are simply key planetary combinations occurring in ones chart that have a certain outcome. The Dasha often times show when that particular combination will bare fruit. For example Warren Buffet has a special combination called a Lakshmi Yoga? Which triggers when the Ascendant Lord is strongly placed, and the Lord of the 9th House is exalted, or in its own sign in a Kendra(1,4,7,10) or Trikona(5, 9) House in a natal chart. This Yoga is known to bring opulent wealth and philanthropic opportunities for a native. So Buffet being a Sagittarius Ascendant has the Lord of the 9th House, Sun in its own house Leo , and the Ascendant Lord Jupiter is placed well in Gemini . The Lakshmi Yoga was activated during his Sun Dasha, which was 7/27/1989 - 7/27/1986. Right at the end of this Dasha he was officially declared a Billionaire. When one blends the activation of a prediction with a Dasha and then validate the prediction with a transit, it makes a serious weapon in predictive astrology without a doubt.