Is Guru mahadasha always favourable?

Usually, but not automatically. It depends on which houses Jupiter rules from your lagna, its sign, and whether it is debilitated in Makara or afflicted. A general benefic ruling difficult houses does not behave like a benefic during its own period.

Why is Jupiter said to aspect three houses?

Jupiter has special aspects on the fifth and ninth houses from itself, in addition to the seventh that all planets aspect. Mars and Saturn have their own special aspects; the rest aspect only the seventh.

What are the remedies during Guru mahadasha?

Tradition suggests the Guru mantra, respect for teachers and elders, donating turmeric or chana dal on Thursday, and study. The practical half is straightforward: a Jupiter period rewards learning something properly.

Guru (Jupiter) Mahadasha

गुरु महादशा

What happens during Guru mahadasha?

Guru mahadasha runs for 16 years. Jupiter is the karaka of wisdom, teachers, children, wealth and dharma, and is the most benefic of the nine in classical reckoning. That reputation is real but conditional: a Jupiter that rules difficult houses for your lagna does not behave like a general benefic during its own period.

The most benefic planet, with a condition attached

Jupiter is the greater benefic, and its sixteen years are generally the ones people hope for. But benefic status in the abstract is not the same as benefic for your chart. For a Vrishabha lagna, Jupiter rules the eighth and eleventh houses, and its period behaves quite differently from the same planet for a Dhanu lagna where it rules the first and fourth. Reading Jupiter as universally good is the mirror image of reading Saturn as universally bad, and it is the same mistake.

Jupiter's aspects make its period wider

Jupiter casts special aspects on the fifth and ninth houses from itself as well as the seventh, which means it touches more of a chart than most planets do. During its own mahadasha this matters: the houses Jupiter aspects tend to be activated alongside the house it occupies. A Jupiter in the third aspecting the fifth, seventh and ninth is quietly influencing children, partnership and fortune throughout its sixteen years.

Children, learning and the sixteen years

Jupiter is the classical karaka for children and for teachers, and its dasha is often associated with both — the birth or growth of children, or a period of study and mentorship. As always the karaka names the subject and the house decides whether it is live: the fifth house and its lord have to support the reading before the mahadasha can deliver it.

Common questions

How long is Guru mahadasha?: Sixteen years.
Is Guru mahadasha always favourable?: Usually, but not automatically. It depends on which houses Jupiter rules from your lagna, its sign, and whether it is debilitated in Makara or afflicted. A general benefic ruling difficult houses does not behave like a benefic during its own period.
Why is Jupiter said to aspect three houses?: Jupiter has special aspects on the fifth and ninth houses from itself, in addition to the seventh that all planets aspect. Mars and Saturn have their own special aspects; the rest aspect only the seventh.
What are the remedies during Guru mahadasha?: Tradition suggests the Guru mantra, respect for teachers and elders, donating turmeric or chana dal on Thursday, and study. The practical half is straightforward: a Jupiter period rewards learning something properly.