The Role of Dashas

The role of dashas is to time the chart. Vimshottari is the system in ordinary use: 120 years divided among the nakshatra lords, Ketu 7, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, Mercury 17. The Moon's nakshatra chooses the opening mahadasha. The balance is the unused fraction of that lord's years. A planet can be exalted and silent until its mahadasha, and a weak planet can dominate a decade because its years have arrived.

Without the dasha you can describe a static kundli. You cannot say when the 7th lord or the 10th lord is allowed to act.

The mahadasha is the container. The antardasha is the lord acting inside it. The length of a sub-period is the product of the two year-counts, divided by 120. Rahu mahadasha is not one flavor for 18 years. Rahu-Venus and Rahu-Saturn are different chapters. People who suffer in a benefic mahadasha are often inside a difficult antardasha, and the container is still the benefic.

Transits trigger what this pair allows. They do not replace it. Saturn over the 10th during Jupiter mahadasha is a Jupiter-era career event with Saturn's weather.

There is no universal best dasha. The 10th lord's period matters for work. The 7th lord's and Venus's matter for marriage. The yogakaraka's period matters for status: Saturn for Taurus and Libra, Mars for Cancer and Leo, Venus for Capricorn and Aquarius. A Venus mahadasha is 20 years of Venus's houses, which may be dusthanas.

Jyothish reads the dasha that is already running, from the birth nakshatra forward. It does not pick a flattering lord and pretend the sequence skipped.