Jiang Li was practicing a body refining technique obtained from the Xuanyuan Sword.
Previously, because of the Divine Farmer's appearance, he had triggered the Xuanyuan Sword. When he realized he was being exploited by the sword, he thought of countering it. Unexpectedly, instead of obtaining the technique from the "Form Tomb", he ended up with the body refining method hidden within the imprint of Chi You.
This method involved refining the physical body with Innate Qi, much like how one refines Qi. The "Qi Tomb" could return to the origin, refining the most pure and original Innate Qi, whereas this method applied the technique to the physical body, reversing the innate process to refine the purest and most primal physical body, which Jiang Li called the Innate True Body.
This method and the "Form Tomb" both focused on the physical body, but their essence differed.