Planets in houses · Kendra
Budh in the 1st house
Mercury · Tanu Bhava
Budh is the karaka (significator) of intellect, speech, business and learning. The 1st house, called Tanu Bhava, shows self, body and personality. When Budh sits here, these matters take on its colour.
A benefic in the Lagna is a blessing: it gives a pleasant nature, good health and a likeable personality, and protects the whole chart.
The 1st house is a kendra (angular house), a pillar of the chart, so a graha here shows its results openly and strongly.
Budh gains directional strength (Dig Bala) in the 1st house, which noticeably strengthens it here.
Budh gives its best results here when it is exalted in Kanya, in its own sign (Mithuna and Kanya) or in a friendly sign, and when it is not combust.
Results are weaker if Budh is debilitated in Meena, combust, or afflicted by malefics.
In transit (gochar)
When Budh transits the 1st house counted from your Moon sign, the period traditionally needs more care.
A single placement is never read alone: sign, aspects, conjunctions, dasha and the whole chart change the outcome.