According to prevalent definition of Simhasana Yoga in Vedic astrology; if in a horoscope, the lord of 1st house is placed in the 10th house or if the lord of the 10th house is placed in the 1st house, Simhasana Yoga is formed in the horoscope. Simhasana Yoga can bless the native with good results related to profession, high authority, fame, reputation and many other things. Such native may achieve a post of high authority in government through job or politics; depending on his overall horoscope.
In real practice, Simhasana Yoga is not seen producing such results when only the aforementioned conditions are met. Hence some other condition should be met in order for this yoga to be formed effectively in a horoscope. Looking at this condition, the lords of the first and/or tenth house should be duly benefic in such horoscope. One such malefic lord may not form this yoga whereas one such partly malefic lord may not form effective Simhasana Yoga in horoscope.
Taking an example, suppose Saturn is placed in the tenth house of a horoscope in Scorpio. Saturn is partly benefic and partly malefic in horoscopes with Aquarius ascendant. Hence Simhasana Yoga may not be formed in the horoscope or it may not work properly; depending on the overall horoscope. The concept of a planet being partly benefic and partly malefic has been explained in the book ‘Pitra Dosh – Ancestors are Calling (Revised Edition)’.
Taking another example, suppose Saturn is placed in the first house of a horoscope in Aries, in Aries navamsha of Ashwini nakshatra. Functional nature of Saturn is flexible in horoscopes with Aries ascendant. In the present case, Saturn is uncomfortable in Aries, in Ashwini nakshatra and in Aries navamsha. Hence it may turn much more malefic than benefic. Therefore, Simhasana Yoga may not be formed in the horoscope or it may not work properly; depending on the overall horoscope. The concept of planets exhibiting tendencies to be benefic or malefic on the basis of the houses they rule in a horoscope has been explained in the chapter ‘Gemstones for House Lords’ of the book ‘Gemstones – Magic or Science (Revised Edition)’.
Taking another example, suppose benefic Jupiter is placed in the tenth house of a horoscope in Sagittarius. Pisces rises in the ascendant and Jupiter rules the first as well as the tenth house. Hence Simhasana Yoga may be formed in this case. Looking at another example, suppose benefic Saturn is placed in the first house of a horoscope in Taurus. Saturn rules the ninth and tenth house in this case and it is benefic. Hence Simhasana Yoga may be formed.
Once the formation of Simhasana 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.
Taking an example, suppose Jupiter is placed in the first house of a horoscope in Gemini, in Capricorn navamsha of Ardra nakshatra. Jupiter rules the tenth house, it is not strong in Gemini and it is debilitated in Capricorn. Hence weak yoga may be formed.
Taking another example, suppose Saturn is placed in the first house of a horoscope in Taurus, in Taurus navamsha of Rohini nakshatra. Saturn is strong in Taurus, it is comfortable in Rohini and it is strong in Taurus navamsha. Hence strong yoga may be formed in this case.
Looking at the running times; when Mahadashas (planetary periods) of malefic planets are in effect; benefic effects of Simhasana 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 Simhasana 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 Saturn Mahadasha.