Rang gi mtshan nyid kyis grub pa is one of the key concepts of Tsong kha pa's Madhyamika philosophy, and Dr. Yoshimizu translates it as pertaining to what is “intrinsically real.” In this paper, I investigate this concept in Tsong kha pa's interpretation of Yogacara philosophy. In my opinion, mtshan nyid refers to the reason or cause of the characters, postulated on the basis of mundane words or concepts, and kyis means “by the power of” (kyi dbang gis as paraphrased by Tsong kha pa himself). This concept reflects the mtshan mtshon gzhi gsum relationship unique to Tibetan Buddhist literature. In this relationship, mtshan nyid means the reason for the predicate mtshon bya to the subject mtshan gzhi. If one takes this reason mtshan nyid as the real existent character of the postulated predicate mthon bya, then that person can grasp the concept of rang gi mtshan nyid kyis grub pa.