There is a very popular dictum from Astrological Classics (BPHS) which says that a natural benefic planet owing a Kendra (Cardinal) house i.e. House # 4,7 or 10 loses its benefic nature. Also when a Malefic planet owns a kendra house (4, 7, or 10), it stops being a malefic. This is referred as blemish of Cardinal house ownership or “Kendradhipati” yog.
So in some ways the lordship of a Cardinal house changes the very basic energy of a planet - A benefic planet stops being benefic and malefic planet stops being malefic. None of the classics give a reason for this to happen though and in today’s world this dictum is seldom used as well. However the reason for this could be clear if we visualize of the correlation between a planetary energy and the energy of a House.
Planets are classified in two categories in terms of basic nature –
Natural Benefic Planets - Jupiter, Venus, Waxing Moon and well aspected Mercury
Natural Malefic Planets – Sun, Mars, Saturn, Rahu (North Node) and Ketu (South node)
This natural tendency of planets remains same in all horoscopes. But for a specific horoscope analysis Temporal Benefic and Temporal Malefic is considered a very important parameter –
Temporal Benefic – Planets owning benefic house such as Trines (1,5,9)
Temporal Malefic – Planets owning malefic houses such as (3,6,11) etc.
So Jupiter and Venus which are the most benefic planets, if they owe houses 3,6,11 they become malefic for a certain Horoscope or Ascendant.
Example - For Libra and Taurus Ascendant Jupiter is considered a temporal malefic planet. Here we see that energy of the House clearly overpowers the natural energy of the Planet.
Lets see what is the nature of the Energy of Kendra or Cardinal houses –
The Kendra houses denotes a natural change of energy. They show transformation from one state to another -
First House – Energy change from Night to Day
Seventh House – Energy Changes from Day to Night
Tenth House – Energy changes from Morning to Day time
Fourth House – Energy Changes from Early night to Deep Night
So the natural energy flow of the Angular houses clearly show a change from one form to another. That makes Cardinal houses not only the most active ones but also the nature of energy sees a shift and this change of energy is applied to the temporal behavior of the Planets.
These times (sunrise, afternoon, sunset and midnight) are also the times when natural energy is at its peak and in Yogic lore they are referred as “Sandhi Kaal” (which mean time of meeting of two different energies).
Thus, just like Jupiter owning 6th House (negative energy) becomes temporal Malefic, Jupiter owing (4th or 7th or 10th house) also sees a change it its temporal energy and ceases to become temporal benefic, which seems to be the basis of Kendradhipati or Blemish of Angular house.