According to prevalent definition of Adhi Yoga in Vedic astrology; if in a horoscope, natural benefics (Jupiter, Venus and Mercury) are placed in 6th, 7th and 8th houses with respect to Moon, Adhi Yoga is formed in such horoscope. This yoga can bless the native with good results related to profession, authority, power, influence, status and many other things.
In real practice, Adhi Yoga is not seen producing such results when only the aforementioned condition is met. Hence more conditions should be met in order for this yoga to be formed effectively in a horoscope. Looking at the first condition, the benefic planets should be functionally benefic for one such horoscope. It means the planets which are naturally benefic but functionally malefic in a horoscope may not form Adhi Yoga in such horoscope. Looking at the second condition, at least two out of three of these planets should be placed in the aforementioned houses, for the formation of Adhi Yoga in a horoscope. Apart from that, Moon should also be benefic in the horoscope; if there are planets in the seventh house with respect to Moon.
Taking an example, suppose Moon is placed in the first house of a horoscope in Aquarius, Jupiter is placed in the eighth house in Gemini and Venus is placed in the seventh house in Leo. Moon is malefic in the horoscope and it casts direct aspect on Venus. Hence Adhi Yoga may not be formed in this case.
Taking another example, suppose Moon is placed in the eleventh house of a horoscope in Cancer, Venus and Mercury are placed in the fifth house in Capricorn; and Jupiter is placed in the fourth house in Sagittarius. All planets are significantly or highly benefic in this case. Hence Adhi Yoga may be formed and it may bless the native with wealth, authority, status and fame among other things.
Once the formation of Adhi Yoga is confirmed in a horoscope, the next factor to check is its strength. The strength of this yoga is calculated through the placements of planets involved in its formation in various signs, nakshatras and navamshas; as well as through the influences of other benefic and malefic planets on them. The overall theme of horoscope and running times (Mahadashas) also affect the strength of this Yoga.
Let’s look at influences of malefic planets on this yoga. Suppose in the same horoscope; malefic Sun is placed in the fourth house in Sagittarius with Jupiter, malefic Ketu is placed in the fifth house in Capricorn with Mercury and Venus; and malefic Rahu as well as Saturn (partly benefic and partly malefic) is placed in the eleventh house in Cancer with Moon. In this case, all planets involved in the formation of Adhi Yoga are afflicted. Hence the strength of this yoga may reduce a lot and the native may not benefit much from it.
Looking at the running times; when Mahadashas (planetary periods) of malefic planets are in effect; benefic effects of Adhi Yoga may reduce. When Mahadashas of benefic planets other than the ones involved in the formation of this yoga are in effect; benefic effects of this yoga may increase. When Mahadashas of the planets involved in the formation of Adhi Yoga are in effect; the native may witness maximum benefits through this yoga. For instance; in the recent example, the native may benefit the most during Moon Mahadasha, Jupiter Mahadasha, Venus Mahadasha and Mercury Mahadasha.