Powerful Transformation elucidates the alchemical principles of development and completion stage practices applied in a sublime manner. What prevents the meditation experiences and realization from arising, are mainly our misdeeds, obscurations and habitual patterns, these can be purified by Vajrasattva Practice. When a yogi attains accomplishment, the obstacles become greater and can be overcome by Vajrakilaya Practice, combined with recognition of mind nature. In the Secret Heart Essence, these two powerful yidams are combined as conduits o realization and accomplishment. These teachings on the hidden treasures of Chokgyur Lingpa by Karmey Khenpo Rinchen Dargye, Kyabje Dilgo Khyentse Rinpoche, Tulku Urgyen Rinpoche, Tsikey Chokling Rinpoche, and Orgyen Topgyal Rinpoche exactly describe how to train.