Matsya Purana — Navagraha Sacrifice for Planetary Pacification and Prosperity
वितस्तिमात्रा योनिः स्यात् षट्सप्ताङ्गुलविस्तृता कूर्मपृष्ठोन्नता मध्ये पार्श्वयोश्चाङ्गुलोच्छ्रिता //
vitastimātrā yoniḥ syāt ṣaṭsaptāṅgulavistṛtā kūrmapṛṣṭhonnatā madhye pārśvayoścāṅgulocchritā //
The yoni (the base-channel or pedestal feature) should measure one vitasti (a span) in length, and be six or seven aṅgulas in width. It should be raised in the middle like the back of a tortoise, and at the sides it should rise by one aṅgula.
This verse is not about pralaya; it is a technical Vāstu/ritual specification describing precise measurements and curvature for the yoni component used in sacred construction.
It supports dharmic duties by prescribing correct standards for building and maintaining sacred spaces; a king (as patron) or householder (as sponsor) gains religious merit by ensuring construction follows authoritative Puranic measurements.
It sets the yoni’s canonical dimensions (1 vitasti long; 6–7 aṅgulas wide) and its convex ‘tortoise-back’ rise, indicating functional drainage/flow and auspicious, text-approved form in Puranic temple architecture.