Classic Hatha Yoga is an ancient discipline that was developed in India to support meditation practice and enhance and accelerate spiritual growth. Beyond its numerous physical benefits, Hatha Yoga is a guide to working with the energy system of the human body. In the first, basic stages of Sadhana (practice), the practitioner focuses mainly on the practice of Asanas, basic Pranayamas, and Kriyas, to improve the flexibility and strength of the body as groundwork for the deeper work on the energy system: purification of the Nadis (energy channels in the body) and activation of the Chakras (energy centres). The Hatha Yoga system contains four main branches: Asana — Physical postures that bring health and balance to the body, and also serve as a tool to develop the Chakras and to purify the Nadis. Pranayama — Breathing exercises aimed to further develop the Chakras, and purify and harmonize the Nadis. Pranayama practice enables the practitioner to enter into deep states of meditation. Mudra — complex exercises that combine Asana, Pranayama, Bandhas (energy locks) and concentration, to arouse and channel Kundalini energy. Kriya — purification techniques that improve the health of the body and allow smooth channeling of vital energies.