The Guru yoga of Je Tsongkhapa combined with the sadhana of his Dharma Protector
This sadhana includes two practices revealed by the Wisdom Buddha Manjushri. The first is a special Guru yoga in which we visualize our Spiritual Guide as Je Tsongkhapa, who himself is a manifestation of Manjushri. By relying upon this practice, we can purify negativity, accumulate merit, and receive blessings. In this way, we shall naturally accomplish all the realizations of the stages of the path of Sutra and Tantra, and in particular we shall attain a very special Dharma wisdom.
The second practice is a method for relying upon the Dharma Protector Dorje Shugdän. Through this, we can overcome obstacles to our practice and create favourable conditions so that we can nurture and increase our Dharma realizations. If we rely upon the Dharma Protector Dorje Shugdän sincerely, our faith in Je Tsongkhapa will naturally increase and we shall easily gain experience of the pure Buddhadharma transmitted directly to Je Tsongkhapa by the Wisdom Buddha Manjushri.
These two practices are the very essence of the New Kadampa Tradition of Mahayana Buddhism. If we practise them regularly and sincerely, we shall reap a rich harvest of pure Dharma realizations, and eventually come to experience the supreme joy of full enlightenment.
An extensive explanation of this sadhana can be found in the book Heart Jewel, by Venerable Geshe Kelsang Gyatso.