The Zhouyi, also known as the I Ching or Book of Changes, is an ancient Chinese text that serves as a divination tool and philosophical guide. It is one of the oldest classics of Chinese literature, dating back to the Western Zhou period (1046–771 BCE). The text consists of a series of hexagrams, which are symbols made up of six lines that can be either broken or unbroken, representing yin and yang. The Zhouyi is not only used for fortune-telling but also offers insights into the natural world and human behavior. Each hexagram is accompanied by interpretations and commentaries that explore themes of change, balance, and harmony. The text has influenced various aspects of Chinese culture, including Confucianism, Taoism, and traditional Chinese medicine.