The munthā's house — The first bhāva — Tanu
Traditional interpretation — Parāśara transmission · BPHS, bhāva significations; Phaladīpikā II
Tanu bhāva carries the self into the chart: the body and its bearing, appearance, temperament, self-regard, and the general course on which a life sets out. The texts make it the reference point for everything else — every other bhāva is counted from here. Uniquely, the first is classed both as a kendra and as a trikoṇa, pillar and blessing at once, which is why the tradition treats a well-supported lagna as the first requirement of a readable chart.
How the bhāva fares is never read from the label alone. Parāśara's method weighs the dignity and placement of the lagneśa, the grahas occupying the first, and the aspects falling upon it — the computed chart beside this passage carries those facts. Phaladīpikā adds that a bhāva prospers when its lord and kāraka stand strong and benefics see it; which of those conditions holds here is a matter of the chart, not of the name.