Answer

If by “pachhalhan” you mean pachchakhkhān / pratyākhyān, then yes — in Jain Dharma, it is very important to take it before tapasya.

You can do physical austerity without it, but that is not complete Jain tapasya. In Jain tradition, tapasya becomes spiritually powerful when it is done with conscious renunciation, proper intention, and discipline.

Explanation

Pachchakhkhān means making a clear vow or formal resolve, such as:

• “I will not eat until this time”
• “I will avoid a certain food”
• “I will observe a fast properly”

It is important because it:

• Purifies intention — tapasya is not just hunger; it is inner discipline.
• Makes the vow firm — once taken, one becomes more careful and devoted.
• Protects from carelessness — without vow, austerity may become irregular or weak.
• Reduces pride — the act becomes humble and religious, not just personal effort.
• Connects tapasya with dharma — in Jainism, austerity should support right conduct and self-restraint.

So, if someone only “suffers through” fasting or austerity without pachchakhkhān, it may be effortful, but it is not the same as proper Jain tapasya.

Spiritual Understanding

In Jain Dharma, the value of tapasya is not only in reducing food or comfort. Its real purpose is:

• to weaken attachment to the body,
• to increase आत्म-नियंत्रण,
• to purify karma,
• and to support the soul’s progress.

Pachchakhkhān gives tapasya its sacred direction. It turns physical restraint into spiritual discipline. Without it, the austerity may remain external. With it, the austerity becomes an inner vow.

Takeaway

So the short answer is: Yes, you may do tapasya without pachchakhkhān physically, but in Jain Dharma that is not the ideal way.

Pachchakhkhān makes tapasya pure, intentional, and spiritually fruitful.