Answer

Your understanding is partly valid: the exact ancient Jain calendrical system used in early scriptural times is not available to us today in a fully continuous, original form in ordinary practice.

However, Jain tradition did not completely “lose” time-reckoning. Jain scriptures, commentaries, and later tradition preserve many important concepts of time, lunar months, paksha, tithis, seasons, festivals, and cosmic time cycles.

Explanation

In Jain Dharma, time is understood on multiple levels:

• Cosmic time — vast cycles such as Utsarpini and Avasarpini.
• Religious observance time — tithis, paksha, months, Chaturmas, Paryushan, Ayambil Oli, Mahavir Janma Kalyanak, Diwali, etc.
• Practical calendar time — the calendar used by Jain communities for festivals and rituals.

The calendar used today by Jain communities is largely based on the traditional Indian lunar calendar system, especially the lunisolar calendar. Different regions and Jain sects may follow slightly different calculations for certain observances.

So, while the broader lunar-based timekeeping continues, the precise original ancient calendar as it may have been used in the earliest Jain scriptural period is not something we can confidently reconstruct in full detail.

Spiritual Understanding

In Jain Dharma, the deeper purpose of the calendar is not merely historical accuracy. Its main purpose is to support:

• Samayik and spiritual discipline
• Observance of sacred days
• Tapasya and self-restraint
• Remembrance of Tirthankars and great souls
• Awareness of the preciousness of time

Even if historical calendar details have changed over time, the spiritual intention remains preserved: to use time for purification of the soul.

Takeaway

It is fair to say that the exact ancient Jain scriptural calendar is not fully preserved in its original practical form. But Jain tradition has preserved the essential lunar framework and, more importantly, the spiritual use of time for sadhana, vrata, tapasya, and inner awakening.