Vimshottari dasha — the 120-year clock in your chart
A birth chart says what is there. The dasha system says when it acts. Vimshottari is the timing framework almost all Indian practice uses, and it is the reason two people with similar charts can be having entirely different decades.
The cycle
The system runs 120 years and divides it among nine grahas in fixed lengths that never change:
- Ketu 7 years · Venus 20 · Sun 6 · Moon 10 · Mars 7
- Rahu 18 · Jupiter 16 · Saturn 19 · Mercury 17
Where you enter it
You do not start at the beginning. You start at the graha ruling your birth nakshatra, and partway through it — the fraction already elapsed is the fraction of that nakshatra the Moon had already crossed when you were born.
This is why the Moon's exact position matters so much, and why a dasha timeline computed from a rounded birth time will be out by months.
Mahadasha and antardasha
Each major period, or mahadasha, subdivides into nine antardashas in the same order and in proportion to the same lengths. A Saturn mahadasha of 19 years contains a Saturn–Saturn sub-period, then Saturn–Mercury, and so on.
In practice the sub-period is what people feel. The mahadasha sets the weather of a decade; the antardasha sets the season, and it is where timing questions are usually answered.
Why the same period lands differently for two people
A Saturn mahadasha is not a fixed experience. What it does depends on where Saturn sits in your chart, which houses it owns there, and whether it is comfortable in the sign it occupies. The same nineteen years can be the stretch in which someone finally builds something durable, or the stretch that asks for more patience than they have.
This is why a dasha timeline alone is not a reading. The timeline says which graha is speaking; the chart says what it has to say.
What it is honestly good for
Dasha analysis is about periods, not events. It describes what a stretch of years tends to ask of you and what it tends to favour, read through what those grahas mean in your specific chart.
It does not predict dated events, and any reading that promises one is going beyond what the technique supports. A period can be described; a date cannot be assigned to something the technique never claimed to see.
Common questions
How is the starting dasha calculated?
From the Moon's exact sidereal longitude at birth. The ruling planet of the nakshatra it occupies is your first mahadasha, and the portion of that nakshatra already crossed is the portion of the period already elapsed.
What is the difference between mahadasha and antardasha?
The mahadasha is the major period, from 6 to 20 years depending on the planet. The antardasha is a sub-period within it, following the same nine-planet order in proportion.
Does the whole 120-year cycle apply to everyone?
The cycle is 120 years, so nobody completes it. Where you enter depends on your birth star, which is why two people can spend their thirties in completely different periods.