Poshdashmi (Poṣa-daśamī) is a Jain festival that celebrates the birth of Parshvanath, the 23rd Tirthankar.

• Meaning and purpose: It marks Parshvanath’s birth (jayanti) and is a time for devotion, reflection, and vows. Devotees often fast or observe austerities to purify the mind and progress on the spiritual path. It emphasizes peace, purification, and the hope of Moksha. These practices are meant to inspire virtuous conduct and self-control.

• When it is celebrated: The celebration spans the ninth, tenth, and eleventh days of the dark half of the Poṣhā/Māgsar month in local calendars. Exact dates vary by region (north Indian vs Gujarati calendars); in practice, communities look to their temple or regional Jain panchang for the precise tithi in a given year. It is commonly observed as Parshvanātha-jayantī. Some communities observe it in late December to early January depending on the local calendar. ( jainknowledge.com)

• Traditions across Digambar and Śvetāmbara: Both sects honor Poṣa-daśamī as Parshvanath-jayantī, though calendar calculations and the exact tithi can differ by region. The essential spirit remains the same: reverence for Parshvanath and commitment to spiritual vows. ( jainknowledge.com)

If you’d like, I can help find the exact Poṣa-daśamī date for your city or temple for a given year. You can read more here and there are related details in the Jain Knowledge resources.