Which form of the Goddess is worshipped on each day of Navarātri?

the Navadurgā — Śailaputrī, Brahmacāriṇī, Candraghaṇṭā, Kūṣmāṇḍā, Skandamātā, Kātyāyanī, Kālarātri, Mahāgaurī and Siddhidātrī.

Day 1 Śailaputrī, daughter of the Himālaya; Day 2 Brahmacāriṇī, the Goddess in penance; Day 3 Candraghaṇṭā, with the crescent moon like a bell; Day 4 Kūṣmāṇḍā, who smiled the universe into being; Day 5 Skandamātā, mother of Kārttikeya; Day 6 Kātyāyanī, born in the sage Kātyāyana’s āśrama; Day 7 Kālarātri, the fierce dark form that destroys fear; Day 8 Mahāgaurī, radiant and calm; Day 9 Siddhidātrī, giver of accomplishment.

This list comes from the Devī Kavaca recited before the Durgā Saptaśatī. In many homes each day also has a colour and a bhoga, though these vary by region and year.

In Bengal and the East the focus is instead on Durgā’s arrival from Ṣaṣṭhī to Daśamī; in the South, the nine nights are often divided into three each for Durgā, Lakṣmī and Sarasvatī.

Source: Devī Kavaca (Durgā Saptaśatī) · Day colours vary by region and year

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