Budha (Mercury) is the kāraka of intellect (buddhi), discrimination (viveka), communication, commerce, and all the faculties through which the mind engages with the material world through language, calculation, and categorization. Parāśara describes Budha as having a greenish, beautiful body, the capacity to speak agreeably and wittily, intelligence of the discriminating type, and a mixed (vāta-pitta-kapha) constitution that reflects Mercury’s essentially adaptive, responsive nature. Mercury’s classification as a conditional graha — benefic when associated with other benefics, malefic when associated with malefics — captures its essential character: Mercury is a mirror, amplifying whatever field it inhabits.
The kārakatva of Budha spans: speech, writing, mathematics, commerce, accounts, medical knowledge (particularly diagnosis), maternal uncles, green things, south-facing places, nervous system, skin, respiratory system, and all activities requiring manual dexterity combined with mental precision. Mercury rules both Mithuna (Gemini) and Kanyā (Virgo), reflecting its two primary modes: the communicative-social Mercury of Mithuna and the analytical-discriminating Mercury of Kanyā. Exaltation in Kanyā at 15° represents Mercury at its highest expression of analytical precision; debilitation in Mīna at 15° places Mercury in the sign of boundless intuition and oceanic consciousness, where the discriminating mind dissolves into a more diffuse, impressionistic mode of knowing.
Mercury is the fastest of the visible planets after the Moon, completing the zodiac in approximately one year but spending only two to four weeks in each sign when direct (longer when retrograde). This speed gives Budha special significance in timing calculations and transit analysis. Mercury’s retrograde periods (occurring approximately three times per year, each lasting about three weeks) are notable in practical Jyotiṣa as periods when communication, contracts, travel, and mechanical systems are subject to review, revision, and occasional breakdown — periods that classical texts recommend for reflection and editing rather than new initiations.
The relationship between Budha and Guru (Jupiter) is philosophically rich in the tradition. Mercury represents the discriminating, analytical, lower mind (manas in its active, categorizing aspect); Jupiter represents the expansive, synthetic, higher mind (mahat or buddhi in its wisdom aspect). Both are required for complete intelligence: Mercury without Jupiter produces clever but shallow rationalism; Jupiter without Mercury produces visionary but impractical idealism. Planets in mutual reception between Budha and Guru positions are traditionally interpreted as producing exceptional intellectual capacity that bridges analysis and wisdom.
Mythologically, Budha is identified as the son of Candra (the Moon) by Tārā, the wife of Bṛhaspati (Jupiter) — a conception that produced one of the famous cosmic conflicts in the Purāṇic tradition (the Tārakāmaya war). This origin myth encodes multiple insights: Mercury as the offspring of mind (Moon) and the cosmic principle of wisdom (Jupiter’s domain through his consort) is the intelligence that bridges emotional and philosophical dimensions. Budha is also sometimes identified with the Vedic deity Sarasvatī in her masculine form, linking Mercury to the arts of language, learning, and cosmic speech.
In Praśna Jyotiṣa, Budha’s condition is central to questions about communication, contracts, educational matters, commercial transactions, travel, younger siblings, and any situation requiring clear information and accurate calculation. A strong Mercury indicates the querent’s intelligence and communicative skill will navigate the matter effectively; a weak or retrograde Mercury suggests confusion, miscommunication, or the need to revisit and revise existing arrangements before they can function optimally. Mercury’s position relative to the Sun (whether combust, cazimi, or clear of the Sun’s beams) also affects its functional strength in Praśna analysis.