The Yin and Yang of Chinese Medicine is well known but as a different language is used in Ayurveda, its version of Yin an Yang is less well known.
Ayurveda describes ten opposite qualities of the Natural World within us and around us (Gurvadi Guna - 20 Qualities).
HEAVY – LIGHT (Guru/Laghu)
COLD – HOT (Sita/Usna)
OILY – DRY (Snigdha/Ruksha)
DULL – SHARP (Manda/Tiksna)
SMOOTH – ROUGH (Slaksna/Khara)
DENSE – LIQUID (Sandra/Drava)
SOFT – HARD (Mrdu/Kathina)
STABLE – MOBILE (Sthira/Sara or Cala)
GROSS – SUBTLE (Sthula/Suksma)
CLOUDY – CLEAR (Picchala/Visada)
When we look over the list it is easy to recognise that the idea of two opposing energies is very similar to the theory of Yin and Yang.
The priniciple of the Yin Yang theory is said to be that 'all things exist as inseparable and contradictory'.
The principle of the ten opposing qualities in Ayurveda comes from the Samkhya philosophy and proposes that the Five Elements (Ether, Wind, Fire, Water, Earth) are the five energies/forces that are always at play in our lives and each Element exemplifies certain Guna or qualities (on a sliding scale between opposites). In Ayurvedic medicine it is these qualities that we bring into our life via diet, movement, lifestyle and remedial therapeutics such as massage. We need them - all of these beautifully differing qualities, in different quantities, according to our Prakrti (Nature) and Vkrti (symptoms of imbalance).
Ether Element is subtle and without friction
Wind Element is rough, dry and mobile
Fire Element is quick, sharp, hot and light
Water Element is slow, smooth and soft
Earth Element is heavy, stable, cool and hard
From this brief (incomplete) list of qualities of each of the Elements we can see that the Earth/Water or 'Hydrate and Hug Inwards' classes can be similar in effect to the idea of a Yin class with long held stretches inviting stillness and quiet mind, focusing on letting the body become heavy, stimulating a softness of deeper layers and stimulating the relaxation response to 'smooth' the nerves.
The Fire/Water or 'Warm and Strengthen' classes are Yang - stimulating, sharpening of mind, strengthening, inviting of action and warmth and penetrating to deeper core strength.
The Ether/Wind or 'Uplift and Mobilise' classes are a blend of powerful Yang inversions and very subtle gentle Yin neck work with both Yin-Yang (powerful and subtle) movements from the chest, shoulders and arms.