Planets in houses · Upachaya
Ketu in the 3rd house
South node · Sahaja Bhava
Ketu is the karaka (significator) of detachment, intuition, spirituality and past karma. The 3rd house, called Sahaja Bhava, shows courage, siblings and effort. When Ketu sits here, these matters take on its colour.
In the 3rd house a malefic is at its best: it gives courage, initiative and the will to win through effort.
The 3rd house is an upachaya (house of growth): results improve steadily with time and effort.
Ketu is a shadow graha and gives the results of the sign lord and conjunct grahas; it is considered strong in Vrishchika.
Results are weaker if Ketu is debilitated in Vrishabha, combust, or afflicted by malefics.
In transit (gochar)
When Ketu transits the 3rd house counted from your Moon sign, the period is traditionally favourable.
A single placement is never read alone: sign, aspects, conjunctions, dasha and the whole chart change the outcome.