In a horoscope, there are some planets which tend to give auspicious results are called ‘Yogakaraka Planets’.
Definition of yoga karaka planets: A planet is said to be a Yoga Karaka when it has lordship over a Trine and Kendra house simultaneously. If this planet is placed in a Kendra or in a Trikona, it will prove specially a Yoga Karaka (bestower of yoga).
In any horoscope 1st, 5th and 9th house are known as Trines whereas 1st, 4th, 7th, and 10th are known as Kendra house. The first house or ascendant have dual lordship - Trine and Kendra house and that is why ascendant is considered as the most important planet in any horoscope. This proves the point that ascendant lord Dasha (Period) is always beneficial unless it is severely afflicted.
In a Cancer ascendant chart, Mars rules over the 5th house, which is a trine house and also rules over 10th house, which is a Kendra house. This makes Mars a yogakaraka planet for Cancer ascendant.
Mars relationship with Moon, Jupiter or even Venus produces a Rajyoga of high quality.That is why even Manglik Yoga/Dosha isn't really applicable to Cancer Ascendant native.
Rahu and Ketu give predominantly the effects, as due to their conjunction with a Bhava Lord or, as due to the Bhava they occupy.
Nodes give their results based on their conjunctions or their placements (if there are no conjunctions).
If Rahu and/or Ketu are in Kendra, receiving a Drishti from or in association with the Lord of a Kona or of a Kendra, it will become Yoga Karaka.
Nodes become Yogakarakas if:
They are placed in Kendra and is aspected by a lord of Kona.
They are associated with lord of a Kendra or a Kona.
The Yoga Karaka planet gives result according to it's occupation, ownership and nature. Having the ownership of two good houses i.e. Kendra and Kona it will give good results of those houses plus good results of house occupied. It will also give results according to its nature say, for example,
In the Taurus ascendant Chart, Saturn is 9th and 10th lord so results of these two Bhavas are like strict observance of religious practice and discipline in service etc., again subject to modifications on account of other associations.
Let us say your yoga-karaka is ill-placed, and is not helping you to get material success (e.g. owning a car) but still in your good time, you will get a free ride in somebody’s or company’s car. So there will be modifications to yoga-karaka for a given Lagna, based on his position in a house, his nature, in which nakashatra placed, in which amsha.
So analysis is needed.
The table below lists Ascendants (Lagna) and its Yogakaraka planet.
In Brihat Parashara Hora Shasthra, it is also mentioned that Yoga karaka planets means those planets who are so because of their working for each other and are helpful in giving wealth, comforts and other worldly joys. Totally, planets who give auspicious effects are Yoga karaka planets.
The Yoga karaka planets are formed with reference to their various situations in the horoscope.
If in a horoscope the planets are in an angle mutually (in 1-4-7-10) and they are in their own signs, in their exaltation signs, or in their friend’s signs, they become Yoga karakas even though they may not be in angle from the Ascendant.
If the planets are in an angle from the ascendant and they are in their friend’s sign, own sign or in their exaltation sign, even then they are Yoga Karakas. If the Yoga Karaka planets are situated in the 10th house, it will be specially or significantly Yoga Karaka and especially auspicious. This statement will apply to both the above mentioned two rules generally.
It is necessary for a planet to be in his own sign, in friend’s sign or in his exaltation sign to be called a Yoga Karaka planet.