Jupiter Mahadasha, Mercury Antardasha (Guru–Budh)

The Mercury antardasha is the third of the nine sub-periods inside the Jupiter mahadasha. 16 × 17 ÷ 120 makes the Jupiter–Mercury sub-period 2 years 3 months 6 days on the classical year of twelve thirty-day months, which is how the texts state it, or 828 days on the solar year of 365.2425 days that the dasha calculator uses.

Mercury’s turn in the Jupiter mahadasha comes only after Jupiter and Saturn have run, which takes 4 years 8 months. When the Jupiter–Mercury sub-period gives way to Jupiter–Ketu, 9 years 24 days of the Jupiter mahadasha remains.

Mercury’s 17 years make every Mercury antardasha 17/120 of the mahadasha containing it, so inside Jupiter’s 16 years the Jupiter–Mercury sub-period is the fourth-longest of the nine.

The Nine Pratyantardashas of Jupiter–Mercury

A pratyantardasha of Jupiter–Mercury is 16 × 17 × its own lord’s years ÷ 14,400, and the nine run in cycle order starting from Mercury. Venus’s is the longest inside Jupiter–Mercury at 136 days and the Sun’s the shortest at 41 days, on the classical year and rounded to the day.

How Jupiter and Mercury Stand to Each Other

On the natural friendship table, Jupiter counts Mercury an enemy while Mercury counts Jupiter neutral. The table is not symmetric, so the Jupiter–Mercury relationship has to be quoted in both directions, as it is here, rather than as one word.

Counted between the signs they own, Gemini is the 7th from Jupiter’s Sagittarius, Virgo is the 10th from Jupiter’s Sagittarius, Gemini is the 4th from Jupiter’s Pisces and Virgo is the 7th from Jupiter’s Pisces. Whatever the ascendant, the houses Jupiter rules and the houses Mercury rules sit at those same distances from each other in the chart, so the Jupiter–Mercury sub-period always joins lordships that far apart.

Mercury is debilitated in Pisces, a sign Jupiter owns. In the Jupiter–Mercury sub-period, then, one lord's dignity is placed on the other’s ground.

The Same Pair the Other Way Round: Mercury–Jupiter

16 × 17 equals 17 × 16, so the Jupiter antardasha of the Mercury mahadasha is exactly as long as Jupiter–Mercury: 2 years 3 months 6 days. Nothing else about Mercury–Jupiter matches. It is the eighth sub-period of Mercury’s 17 years rather than the third of Jupiter’s 16; it opens after 12 years 15 days of the Mercury mahadasha, against 4 years 8 months here; and its pratyantars start from Jupiter instead of Mercury.

What the Texts Assign to Jupiter and Mercury

The karaka list the tables give Jupiter, the mahadasha lord, is children, teachers and gurus, higher learning and dharma; for Mercury, the lord of the Jupiter–Mercury sub-period, it is speech, writing, trade, accounts, mathematics, maternal uncles and students. Parashari practice reads the sub-period through the houses each of the two owns and occupies in the birth chart, and through where Mercury stands counted from Jupiter there. None of that is a forecast, and this page makes none: without a chart, Jupiter–Mercury is a length and a position, and the 2 years 3 months 6 days above is the whole of what can be said about it in general.

A birth with the Moon in Punarvasu, Vishakha or Purva Bhadrapada opens life inside the Jupiter mahadasha itself, part-way through, and whether the Jupiter–Mercury sub-period is still ahead depends on how far the Moon had gone into the nakshatra. For a birth in Ashlesha, Jyeshtha or Revati, the Mercury mahadasha comes first, and the Jupiter mahadasha is the eighth in that sequence.

The Other Sub-Periods of the Jupiter Mahadasha

The full table for the Jupiter mahadasha, with where each sub-period opens and closes, is on the Jupiter mahadasha page. How the Jupiter mahadasha is read as a whole is in our Jupiter mahadasha article, and the system itself in Vimshottari dasha explained. This page in Hindi: गुरु महादशा में बुध अंतर्दशा.