Jāti Smaraṇa Jñāna (जाति स्मरण ज्ञान) means knowledge of remembering past births.

In Jain Dharma, it is the ability to recall one’s previous lives, births, and related experiences. This knowledge may arise due to:

• strong right faith and spiritual purity,
• austerity and meditation,
• the rise of keval jñānāvaraṇīya karma-reducing conditions,
• or by divine-type special cognition in very rare cases.

In simple words:

A person with jāti smaraṇa jñāna can remember:

• who they were in a previous birth,
• what actions they did,
• and sometimes the suffering or happiness they experienced before.

In Jain tradition:

This is considered a special type of knowledge and can inspire:

• vairāgya (detachment),
• fear of sin,
• and stronger faith in karma and samsāra.

Important note:

It is not the highest knowledge in Jainism. The highest is Keval Jñāna, the omniscient knowledge of a Tirthankar or Kevali.

If you want, I can also explain how jāti smaraṇa jñāna arises in Jain scriptures.