Matsya Purana — Soma
कुहूमात्रं पित्रुद्देशं ज्ञात्वा कुहूमुपासाते तमुपास्य ततः सोमं कलापेक्षी प्रतीक्षते //
kuhūmātraṃ pitruddeśaṃ jñātvā kuhūmupāsāte tamupāsya tataḥ somaṃ kalāpekṣī pratīkṣate //
Knowing that the rite intended for the Fathers (Pitṛs) is confined to the tithi called Kuhū, one should observe and honour Kuhū. Having observed it, one then waits for Soma (the Moon), looking for the proper kalā, the lunar digit.
This verse is not about Pralaya; it focuses on ritual timekeeping—specifically how ancestor-directed rites are tied to the Kuhū lunar observance and the Moon’s phases (kalā).
It frames a dharmic duty: a householder (and by extension a king as guardian of dharma) should perform Pitṛ-related rites on the correct tithi—honouring Kuhū first and then proceeding in accordance with the Moon’s kalā.
The significance is ritual (not architectural): it prescribes correct timing for Pitṛ-rites, emphasizing Kuhū observance and careful alignment with Soma’s lunar digit (kalā) for proper performance.