Buddhi Yoga
The Sanskrit word buddhi (from the root budh, awaken, observe, understand, etc.) is often translated as “intellect,” but in this context might be more usefully translated “discrimination” or “insight.” The word yoga (from the root yuj, unite, attach, etc.) in this context means a discipline leading to union with one’s Self of atman. The expression “Buddhi Yoga” was used by Swami Venkatesananda to describe the yoga of understanding arising out of the Bhagavad-Gita, in other words, direct realization of Reality. Although the Gita describes Karma, Bhakti, and Jñana Yoga, the first (2.39) and last (18.57) yogas mentioned are Buddhi Yoga. According to the rules of Sanskrit textual interpretation, that is the general purport of the entire text. See further BHAGAVAD-GITA.
R.W.B