Matsya Purana — Navagraha Sacrifice for Planetary Pacification and Prosperity
कोटिहोमे चतुर्हस्तं चतुरस्रं तु सर्वतः योनिवक्त्रद्वयोपेतं तदप्याहुस् त्रिमेखलम् //
koṭihome caturhastaṃ caturasraṃ tu sarvataḥ yonivaktradvayopetaṃ tadapyāhus trimekhalam //
For the Koṭi-homa, one should make the kuṇḍa (fire-pit/altar) four cubits in measure, square on all sides, furnished with a yoni and with two mouths/openings; this too is called the “trimekhala” (the three-girdled form).
This verse is not about Pralaya; it belongs to the Matsya Purana’s Vastuvidya stream, prescribing the geometry and features of a ritual fire-structure (kunda/vedi) for a specific homa.
It supports the dharma of correct ritual performance: a king or householder sponsoring major rites like the Koṭi-homa must follow precise, text-authorized measurements and layouts to ensure the rite is valid and efficacious.
It specifies a four-cubit square kunda/altar ‘on all sides’ and classifies it as trimekhala when equipped with a yoni-feature and two mouths/openings—technical markers used in Puranic ritual-architecture and kunda typology.