Answer

In Jain Dharma, both Pratikraman and Attham Tap are spiritually powerful, but they work in different ways.

• Pratikraman is powerful for repentance, self-purification, forgiveness, and correction of faults.
• Attham Tap is powerful as a form of tapasya, helping reduce attachment to the body and burn karmas through austerity.

If you are asking specifically about the last day of Paryushan / Samvatsari Pratikraman, it is considered extremely important because it includes deep repentance and universal forgiveness through Micchāmi Dukkaḍaṃ.

Explanation

It is not exactly correct to compare them as “which is more powerful,” because:

• Pratikraman purifies the soul through awareness, repentance, confession, and resolve not to repeat mistakes.
• Attham Tap purifies through fasting and endurance, when done with right faith, humility, and inner detachment.

In Jain Dharma, external tapasya becomes spiritually meaningful only when it is joined with inner purity. A fast done with ego, anger, or pride loses much of its spiritual value. Similarly, Pratikraman done mechanically without true repentance also becomes less effective.

Spiritual Understanding

The heart of Jain practice is bhāv — inner intention.

A sincere Samvatsari Pratikraman with true repentance and forgiveness can be deeply transformative. An Attham Tap done with pure intention, equanimity, and humility is also highly meritorious and karmically powerful.

But if one has to understand the essence:

• Pratikraman cleanses the mind and conduct.
• Attham Tap disciplines the body and passions.

Ideally, they support each other. Tapasya without repentance is incomplete, and repentance becomes stronger when supported by restraint and discipline.

Takeaway

Neither should be seen as a competition. In Jain Dharma, the most powerful practice is the one done with right faith, humility, repentance, forgiveness, and pure intention.

If possible, doing Attham Tap with proper Pratikraman is spiritually very beneficial.