Today is this tenth day of twelfth Tibetan month, when Guru Rinpoche is welcomed by Indrabhūti, the king of Uḍḍiyāna, who invests him as crown prince, and he takes Prabhāvatī as his princess and governs the kingdom according to the Dharma, and he is thus known as Guru Pema Gyalpo.
To honor this day, Nekhor offers a new translation - “The Invocation of Uḍḍiyāna on the Tenth Day” discovered by Ratna Lingpa.
In this treasure from Ratna Lingpa (1403-1479), Padmasambhava prophesizes the many ways in which he will reveal himself to disciples in the future. He encourages his students to supplicate him every 10th day of the month, and then gives specific instructions on how to practice the gaṇacakra on these days. It ends with information on the identity of the destined revealer of this treasure, that is, Ratna Lingpa.
http://www.lotsawahouse.org/tibetan-masters/ratna-lingpa/tenth-day-invocation
May it be auspicious!