Kendra, trikona, dusthana and upachaya houses explained

The table above is the fastest answer. It comes from P.V.R. Narasimha Rao (PVR), author of Vedic Astrology: An Integrated Approach, and lists the four main groups with his one-line summary of each.

Kendra (quadrant or angle): the 1st, 4th, 7th and 10th. Trikona (trine): the 1st, 5th and 9th.

Upachaya (houses of growth): the 3rd, 6th, 10th and 11th. Dusthana (difficult houses, also called trik sthanas): the 6th, 8th and 12th.

Notice the overlaps: the 1st, 10th and 6th each sit in two groups. Groups are labels for how a house is read, not boxes a house can belong to only once.

Three smaller groups round out PVR's list: the panapharas (succedants) are the 2nd, 5th, 8th and 11th; the apoklimas (precedants) are the 3rd, 6th, 9th and 12th; the chaturasras are the 4th and 8th.

PVR quotes the traditional imagery: 'Trines are the abode of Goddess Lakshmi, who rules prosperity', and trines from any reference bring prosperity and well-being to whatever that reference stands for.

Quadrants 'are the abode of Sri Maha Vishnu'. The 1st house (the self), 4th (comforts), 7th (marriage and relations with others) and 10th (profession) 'sustain each other'.

Upachayas from any reference 'show forces causing gains and growth to the matters signified by the reference'. PVR applies the same reading when upachayas are counted from other reference points.

Dusthanas from a reference 'show forces causing setbacks to the matters signified by it'. But PVR adds a twist: 'If a dusthana is weak, it shows that obstacles will be easily overcome.' So an exalted 8th lord (a strong ruler of the 8th house) 'may show a lot of troubles', while a debilitated 8th lord (a weak one) 'may show easy sailing'.

Three houses wear two labels at once. The 1st is both a kendra and a trikona, and the Brihat Parashara Hora Shastra (BPHS, R. Santhanam's translation) says of its ruler: 'The Lord of Lagn is specially auspicious, as Lagn is a Kendr, as well as a Kon' (the lagna is the ascendant, the 1st house).

The 10th is both a kendra and an upachaya. The 6th is both an upachaya and a dusthana.

The purusharthas (the four aims of life in Indian thought) each get a set of three houses in PVR's scheme. Read the table above: dharma (duty, righteousness) sits in the 1st, 5th and 9th; artha (money and career) in the 2nd, 6th and 10th; kaama (desire) in the 3rd, 7th and 11th; moksha (liberation) in the 4th, 8th and 12th.

Each set is the trines from a starting point: the dharma set counts from the 1st, the artha set from the 2nd, the kaama set from the 3rd and the moksha set from the 4th. That is the general rule underneath: groups can be counted from any house or reference point, not only the lagna.

PVR's example: the trines from the 3rd house are the 3rd, 7th and 11th, and the quadrants from the 3rd are the 3rd, 6th, 9th and 12th. This also explains planets in relation to each other: planets in mutual trines make each other prosper, and planets in mutual quadrants 'have a sustaining effect on each other'.

One more split: the visible and invisible half. The 7th to 12th houses form the visible half and 'give results that can be seen in the material world'; the 1st to 6th form the invisible half and 'give results that cannot be easily seen'.

Each house has a lord: the planet that rules the sign sitting in that house. BPHS chapter 34 gives lordship rules group by group.

Its summary: 'Benefics, owning Kendras, will not give benefic effects, while malefics, owning Kendras, will not remain inauspicious. The Lord of a Kon will give auspicious results.' A benefic is a planet traditionally read as helpful, a malefic as harsh; a Kon is a trine.

BPHS continues: 'Putr and Dharm Bhava are specially for wealth, while Yuvati and Karm Bhava are specially for happiness' (the 5th and 9th, and the 7th and 10th). 'Any Grah, owning Sahaj, Ari, or Labh Bhava, will give evil effects' (the 3rd, 6th and 11th). The results of the 12th and 8th lords 'will depend on their association', meaning the planets they sit with.

PVR restates this functionally: trine lords are functional benefics, lords of the 3rd, 6th and 11th are functional malefics, and a planet owning both a quadrant and a trine becomes a yogakaraka.

Groups also explain raja yoga (a combination traditionally read as success). When the lord of a kendra and the lord of a trikona are associated, by conjunction, mutual aspect or exchange of signs, they form a raja yoga; when the 9th and 10th lords do this, it is called Dharma-Karmadhipati yoga.

B.V. Raman, in Hindu Predictive Astrology, lists the trines as the 5th and 9th only, leaving out the 1st.

He also calls the 2nd, 5th, 8th and 11th 'Cadent houses (Panaparas)' and the 3rd, 6th, 9th and 12th 'Succeedent houses (Apoklimas)', the reverse of PVR's English labels (succedants and precedants). His kendras (1, 4, 7, 10) and upachayas (3, 6, 10, 11) match PVR's.

BPHS itself differs from PVR in one more place. Chapter 11 groups the lords of the 3rd, 6th, 8th, 11th and 12th as lords of 'evil and such other Bhavas', a wider list than PVR's dusthanas of the 6th, 8th and 12th. These are differences of framing within the tradition, and Skybond presents PVR's tables as the default while showing alternatives alongside.