Yin and Yang literally means “shadow and light”, and Yin-Yang Dualism has been used in Chinese philosophy to describe the interactions between two forces.
Yin
Represents the dark side of everything.
Characterized as: cold, wet, negative and passive.
Associated with: water, earth, the moon, femininity, and night time.
Yang
Represents the light side of everything.
Characterized as: hot, dry, positive, and aggressive.
Associated with fire, sky, the sun, masculinity, and daytime.
Yin and Yang ties into the Japanese Zodiac by assigning a Yin and a Yang force to each of the five earthy elements, resulting in ten possible combinations. The Japanese names for Yin and Yang are:
Yang: 陽（“you” in romaji）
Yin: 陰（”in” in romaji）
Determining if your birth year is Yin or Yang
If the last digit of the year you were born in is odd (i.e. 1,3,5,7,9), you are a Yin. If even (i.e. 0,2,4,6,8), then you are a Yang.