Q: What is the Kalachakra Tantra?
A: The so-called Kalachakra Tantra refers to the Kalachakra Root Tantra. This tantra was preached by Shakyamuni Buddha in his Sambhogakaya form, Kalachakra, to King Chandrakirti of Shambhala and his retinue at the Sri Dhanyakataka Stupa in modern-day Dharanikota, India. At that time, the Buddha was thirty-eight years old. On the fifteenth day of the month of Spica (the third month of the Tibetan calendar), he bestowed empowerment upon Chandrakirti, maturing his mindstream, and then preached the Kalachakra Root Tantra in twelve thousand verses. This is the Kalachakra Tantra as it is widely recognized.