The Dashaya-Ni'Var was a unique Mind meld ritual known to the Vulcan species and meant "to separate that which has become one". It was designed in unique cases where the katra of a dead Vulcan was unwilling to leave the mind of another thus forcing them to become a Val'reth. Through the Dashaya-Ni'Var, a meld was made that was designed to remove the intruding katra from the mind of the victim and place it within a vre'katra. However, the procedure was noted for being dangerous and could potentially lead to the death of the patient.
Its usage predated the coming of Surak and there were no account of it being practiced by modern times. In fact, many refused to acknowledge the existence of the ritual with it being believed that only a small number of adepts capable of this technique with even fewer willing to try it. There were some scrolls that were centuries old that contained all the noted facts about the technique which was cloaked in secrecy with these manuscripts being chronicled in an obscure dialect of the ancient High Vulcan language which had not been used since the time before Surak. By the 23rd century, the Healer Sobon had learnt this ancient technique and performed it in 2267 on T'Prynn in order to remove the invasive presence of her betrothed Sten from her mind. (VAN novel: Open Secrets)