[Yin]: Noun. In Chinese philosophy this is the passive female principle of the universe, characterized as female and sustaining and associated with earth, dark, and cold.
Yin Yoga is a slow-paced style of yoga with postures or asanas that are held for longer periods of time—five minutes or longer per pose is typical.
Yin Yoga poses apply moderate stress to the connective tissues—the tendons, fascia, and ligaments—with the aim of increasing circulation in the joints and improving flexibility. Yin Yoga poses are also designed to improve the flow of qi, the subtle energy said in Chinese medicine to run through the meridian pathways of the body. Improved flow of qi is hypothesized to improve organ health, immunity, and emotional well-being.
Yin is referred to as a more meditative approach to yoga, as it aims at cultivating awareness of one's inner silence, eventually bringing to light a universal, interconnecting quality. However, it is not a replacement for meditation itself.
Yin Yoga is not intended as a complete practice in itself, but rather as a complementary practice to balance the effects of more active forms of yoga and exercise such as Hatha Vinyasa, Hot Yoga or Ashtanga.